2.1 Definition of ER

Reading extensively is how children become literate in their mother tongues. There is a saying in Chinese “读万卷书, 行万里路,” which can be literally translated as “Read ten thousand books, travel ten thousand miles” to denote the importance of reading in Chinese culture. In their seminal book Extensive Reading in the Second Language Classroom, Day and Bamford (Reference Day and Bamford1998) systematically proposed ER as an approach to teaching and learning reading in a foreign or second language. ER involves reading large quantities of comprehensible texts. ER is also called pleasure reading, free voluntary reading, and sustained silent reading (Jeon & Day, Reference Jeon and Day2016).

Day and Bamford (Reference Day and Bamford1998) defined extensive reading in a second language as “an approach to the teaching and learning of second language reading in which learners read large quantities of books and other materials that are well within their linguistic competence” (p. viii). Carrel and Carson’s definition of ER is “extensive reading … generally involves rapid reading of large quantities of material or longer readings (e.g., whole books) for general understanding, with the focus generally on the meaning of what is being read than on the language” (Reference Carrel and Carson1997, pp. 49–50). Grabe and Stoller (Reference Grabe2011) defined ER as “an approach to the teaching and learning of reading in which learners read large amounts of materials that are within their linguistic competence” (p. 286). Though the definitions by Day and Bamford (Reference Day and Bamford1998), Carrel and Carson (Reference Carrel and Carson1997), and Grabe and Stoller (Reference Grabe2011) differ slightly, what they share is first, ER involves reading a large amount of materials, and second, reading materials need to be comprehensible to readers. Those two features reflect the unique nature of ER and are reflected in two of the ER principles proposed by Day and Bamford (Reference Day and Swan1998, Reference Day and Bamford2002) (See section 2.3).

This approach completely differs from traditional approaches of teaching reading (such as intensive reading) in terms of “the quantity of reading, the difficulty level of the reading, the freedom students have to choose books, the degree of autonomy enjoyed by the students, and the motivation to continue reading” (Nakanishi, Reference Nakanishi2015, p. 9). Nation (Reference Nation2006) believed that through input at their level of proficiency, reading becomes a source of learning as well as a source of enjoyment.

After a discussion of its definition, the next section will focus on theories underlying ER.

2.2 Theories Underlying ER

In this section, I will discuss theories underlying ER. Those theories either provide theoretical justifications and rationales for the significance of ER or support the implementation of ER in language programs. One theory is Comprehensible Input Hypothesis proposed by Krashen, and the other three are Lexical Efficiency Hypothesis, Lexical Quality Hypothesis, and Lexical Constituency Model proposed by Perfetti and his colleagues. Since the latter three are closely related to each other, they will be discussed as one theory.

Comprehensible Hypothesis claims that we acquire language when we understand it, that is, when we get “comprehensible input” (Krashen, Reference Krashen1981). Comprehensible Hypothesis is a combination of two hypotheses, Input Hypothesis and Goodman/Smith Hypothesis, which states that reading is a natural process and learning is subconscious (Krashen, Reference Krashen and Patricia2009). Krashen stated that Comprehensible Hypothesis holds for “first and second language acquisition, oral and written language, children, teenagers, and adults” (p. 57). There are a few key claims in this hypothesis. First, to facilitate language acquisition, the language input must be comprehensible. Krashen (Reference Krashen and James1992) stated that “only comprehensible input is effective in increasing proficiency (p. 411). The more comprehensive input there is, the more language acquisition there will be. Second, language input needs to be interesting so that language learners or acquirers will pay attention to it. Third, a low affective filter or open attitude is needed. Krashen stated that activities that students reported to be least anxiety-provoking or non-anxiety-provoking, such as silent reading, seem to be very efficient in enhancing language acquisition. Lastly, the components of language such as vocabulary, grammar, spelling, writing, and so on are the results of getting comprehensible input. Numerous studies have shown that language was acquired merely by learners being very interested in reading (Krashen, Reference Krashen and Patricia2009). For example, Krashen reviewed the Fiji Island study which showed that in-school free reading has a powerful effect on second language learners. The study divided a group of fourth- and fifth-grade students studying English as a second language into three groups. The first group used the audio-lingual method, an approach that emphasizes drill, repetition, and heavy grammar instruction. The second group did a free reading for the entire class (i.e., thirty minutes). In the third group, the teacher read the book to the students, students discuss the book, read it together, act out the story, and draw parts of the book. After two years, the free reading group and the shared reading group were superior to the traditional group in reading comprehension, vocabulary, and grammar tests. Another study that Krashen believed should be mentioned whenever free voluntary reading is discussed is the Hooked on Books project conducted by Daniel Fader and Elton McNeil (1968) (as cited in Krashen, Reference Krashen and Patricia2009). They encouraged adolescent boys in a reform school to read newspapers, magazines, and paperback books. Students were also encouraged to share what they read with the class. After one year, the Scholastic Achievement Test scores showed that their reading comprehension scores increased by more than one entire grade level (1.3 years) and were twice as much as the scores of the students who did not read for pleasure. Thus, vocabulary, grammar, spelling, writing, and so on are the results of getting comprehensible input and can be learned incidentally through being immersed in reading.

Comprehensible Hypothesis is an important theory underlying ER since it highlights the importance of providing language learners comprehensible and interesting input and creating a low-anxiety environment, and as a result, different aspects of a foreign language will be acquired subconsciously.

Another theory underlying ER is related to word recognition. Lexical Efficiency Hypothesis, Lexical Quality Hypothesis, and Lexical Constituency Model, all attach great significance to the efficiency and quality of word recognition, an essential lower-level processing in reading. The hypotheses were proposed and tested by Perfetti and his colleagues (Reference Perfetti1985, Reference Perfetti, Gough, Ehri and Treiman1992, Reference Perfetti, Brown and Hagoort1999, Reference Perfetti2007). Perfetti developed Lexical Efficiency Hypothesis in his book: Reading Ability (Reference Perfetti1985). This model assumes that for skilled readers, lower-level processing is relatively automatized. Word identification, the rapid retrieval of a word’s phonology and meaning, is essential for comprehension. Lexical Efficiency Hypothesis was based on the notion that attention and working memory are limited resources. Efficient word recognition skills make fewer demands on attention and working memory and allow limited cognitive resources to be used for other higher-level comprehension processes, such as integrative processes, inferences, and syntactic repairs. According to Lexical Efficiency Hypothesis, each reader has a unique profile of verbal efficiency. The more efficient a reader’s verbal efficiency is, the more cognitive resources can be allocated to higher-level processing. As a result, lexical efficiency, as the automatic and resource-cheap word-level processes, was assumed to support comprehension (Perfetti, Reference Perfetti2007). Readers who have problems with higher-level comprehension skills may have inefficient word-identification skills (Grabe, Reference Grabe2009).

Lexical Efficiency Hypothesis is concerned with word reading fluency and decoding speed. It seems that by increasing the word recognition efficiency, the comprehension will be improved. However, an increase in word identification efficiency does not necessarily lead to better comprehension (Perfetti, Reference Perfetti2007). Reading fast at the word level does not mean an accurate retrieval of word meaning and phonology that the reader needs in a given context. In order to have an accurate retrieval of word identification, a high-quality lexical representation is needed. Lexical quality refers to “the extent to which the readers’ knowledge of a given word represents the word’s form and meaning constituents and knowledge of word use that combines meaning with pragmatic features” (Perfetti, Reference Perfetti2007, p. 359). Lexical quality is more about the depth of vocabulary knowledge, about whether the reader knows the form, the pronunciation, the meaning, and the usage of a word.

Lexical representation quality can be high or low. In order to distinguish high- and low-quality representations, Perfetti (Reference Perfetti2007) identified five features of lexical representation and three consequences of those features on the reading process. The representative features are the constituents of word knowledge: phonology, orthography, meaning, and grammar. Another feature, constituent binding, refers to the degree to which the four features, phonology, orthography, grammar, and meaning, are bound together to form a word’s identity. The consequence of high lexical representation quality is stable and synchronous retrieval of a word from a mental lexicon, which is available for building comprehension. Low lexical representation quality, on the other hand, often leads to failure in retrieving the word identified from the mental lexicon, thus causing obstacles to comprehension.

Lexical representation quality to the accuracy and fluency of word identification. The higher quality the word representation is in a reader’s mind, the faster and more accurately the word’s identity will be retrieved. Also, the lexical representation quality may be related to different constituents of word knowledge. Some readers may have quality problems with the semantic constituent of a word; for most readers, the quality problem cuts across phonological, meaning, and orthographic constituents. Furthermore, readers differ in their word representations. Lexical representation quality is “graded across words for a given individual and across individuals for a given word” (Perfetti, Reference Perfetti2007, p. 380). Finally, lexical representation quality originates from language experience. The more experience a reader has with a word, the better and more stable his lexical representation will be.

Both Lexical Efficiency Hypothesis and Lexical Quality Hypothesis were proposed based on research on alphabetical languages. Based on research on word reading in Chinese and alphabetical languages, Perfetti (2007) proposed the Lexical Constituency Model. The model assumes that a word representation consists of three interlocking constituents (or variables): orthography (OR), phonology (PH), and semantics (SE). Orthographic, phonological, and semantic constituents specify word identity. Thus, to identify a word involves the retrieval of a phonological form and meaning information from a graphic form. An absence of any one of the three constituents would result in an underspecified identity. Perfetti (Reference Perfetti2007) emphasized that the constituency framework is universal and not related to a specific writing system.

Lexical Efficiency Hypothesis, Lexical Quality Hypothesis, and Lexical Constituency Model provide strong theoretical support for extensive reading research and practice. ER provides meaningful contexts for the acquisition of words. The more learners read, the faster they recognize words. Numerous empirical studies have also provided evidence for the learning of different aspects of vocabulary knowledge (e.g., spelling, meaning, and usage) through reading. A large sight vocabulary size enables the efficient and automatic recognition of words. As a result, this efficient, automatic, and high-quality lower-level processing will enable more cognitive recourses to be allocated to higher-level processing.

Nassaji (Reference Nassaji2014) stated that there are three perspectives in the past few decades regarding both L1 and L2 reading research: bottom-up, top-down, and interactive views of reading (p. 2). The bottom-up approach views reading as “consisting of a series of successive stages, starting with a visual analysis of letters and sounds, then combining them to construct phrases and sentences, and finally building a semantic representation of the text” (Nassaji, Reference Nassaji2014, p. 2). Top-down approach views reading as primarily a “reader-driven activity” (p. 2) and that reading comprehension mainly relies on readers’ conceptual and background knowledge. Readers verify top-down hypotheses by using strategies such as predicting and guessing (e.g., Goodman, Reference Goodman, Goodman and Goodman2014). The interactive view perceives reading as composed of several component skills that interact with each other. Though the three perspectives have been proposed and tested in reading research, a feature of the most current view of L2 reading, as Nassaji (Reference Nassaji2014) has pointed out, is the importance of lower-level processes.

To conclude, efficient reading comprehension in a second language (L2) hinges on the reader’s proficiency in lower-level processes. These foundational skills are essential for allocating cognitive resources effectively to more advanced levels of comprehension. As evidenced in Nassaji’s (Reference Nassaji2014) systematic review, even advanced L2 readers rely significantly on these lower-level processes. An important takeaway from Comprehensible Hypothesis, Lexical Efficiency Hypothesis, Lexical Quality Hypothesis, Lexical Constituency Model, and the current L2 reading research is the need for L2 reading instruction to focus on developing these essential lower-level skills. In this context, extensive reading emerges as a pivotal method of teaching and learning reading. It improves L2 reading comprehension and language proficiency in general through facilitating the enhancement of these crucial lower-level processes.

2.3 ER Principles

Since ER is an approach to teaching and learning L2 reading, language teachers need to know how to implement ER in their language classrooms. Day and Bamford (Reference Day and Bamford2002, pp. 137–140) proposed the ten principles of implementing ER.

2.4 Types of ER

There might be no single type of ER. Based on whether ER programs fully or partially followed the ten ER principles, Day (Reference Day2015) classified ER into four types: pure ER, modified ER, ER light, and fringe ER. Pure ER uses all the ten ER principles. Modified ER, as Day (Reference Day2015) put it, uses many ER principles. ER light uses some of ER principles. The last one, fringe ER, uses none of the ten principles, thus it is “ER in name only” (p. 296).

Given the various types of ER and different practices of ER, Day (Reference Day2015) suggested that ER principles can be used based on the nature of ER programs. An examination of ER literature reveals that language teachers use a variety of labels to describe their ER programs. The following are some examples.

3.1 Reading Fluency

Reading fluency is a critical concept in both L1 and L2 reading research. According to Kuperman et al. (Reference Kuperman, Siegelman and Schroeder2023), “high reading proficiency is not only about comprehending the text being read but also doing it fluently” (p. 8). Fluency is viewed as an essential step in the comprehension of reading texts. Fluent reading involves automaticity. Reading fluency refers to the ability to automatically recognize an increasing number of words and phrases (Day, Reference Day2013; Taguchi et al., Reference Taguchi, Takayasu-Maass and Gorsuch2004). Fluent reading also involves accuracy. When people read fluently, the automatic word recognition is always accurate (Day, Reference Day2013). Words that readers recognize quickly, rapidly, and accurately, are called sight vocabulary. Fluent readers have effective and efficient word recognition skills and thus usually have a large sight vocabulary. When learners encounter the same words many times, these words may enter their sight vocabulary (Day & Bamford, Reference Day and Bamford1998). Day (Reference Day2013) viewed sight vocabulary as one point on the continuum of reading vocabulary. On one end of the continuum are words that readers don’t know. In the middle of the continuum are words that are in the readers’ general vocabulary. General vocabulary requires readers to pause for one or two seconds to recall their meaning (Day, Reference Day2013). When learners read a lot, they encounter words that are part of their general vocabulary. When readers come across the same words over and over again, the general vocabulary may enter into readers’ sight vocabulary. This is how extensive reading helps readers become fluent readers.

Thus, it is critical that learners have opportunities to keep seeing the words that they have seen before. Iwahori (Reference Iwahori2008) investigated how ER improved the reading speed among thirty-three Japanese high school EFL learners. The students were asked to read twenty-eight books (graded readers and comic books) over seven weeks. Students’ reading rate was assessed at the beginning and end of the ER treatment through one-minute reading probe method (i.e., word per minute [WPM]). The results of a paired t-test revealed that there was a significant reading rate increase, from 84.18 WPM (pre-test) to 112.82 (post-test). The increase of 28.64 WPM indicated that reading rates were shown to increase by about 30 percent in the ER treatment period. Similarly, after reading on Xreading.com for one year, the 11 advanced, post-tertiary L2 learners in Tabata-Sandom (Reference Tabata-Sandom2023) increased their reading rate from 123.8 WPM to 153.2 WPM, an increase rate of 23.6 percent. In another study, seventeen English learners from a university in Vietnam read on an online extensive reading website for ten weeks (Bui & Macalister, Reference Bui and Macalister2021). The average number of words read by the participants in 10 weeks is 23,409 words. Bui and Macalister (Reference Bui and Macalister2021) used four methods to calculate the reading rate increase and the most conservative method showed the participants’ reading speed on average increased thirty-six WPM, which is approximately an increase of 23%. Almost 70% of the participants (twelve out of seventeen) agreed that the online ER program helped them read more fluently.

While investigating reading fluency, ER has also been compared or combined with other approaches. Bell (Reference Bell2001) investigated extensive reading versus intensive reading with young adult EFL learners in Yemen and compared the reading rate changes of the two groups. The intensive reading group’s reading rate increased from 78.45 WPM to 92.54 WPM, while the ER group increased from 68.10 WPM to 127.53 WPM. In a similar vein, after reading extensively for one semester, 34 first-year Japanese EFL students at a private, four-year nursing college in Japan improved their reading speed from 110.59 WPM to 131.33 WPM (Huffman, Reference Huffman2014), which was similar to that achieved by the group that read simplified texts (16.85 WPM) in Beglar et al. (Reference Beglar, Hunt and Kite2012). Research has also shown that the participants who read the most made the greatest reading rate gains (Beglar & Hunt, Reference Beglar and Hunt2014).

The average silent reading rate for adults in English is 238 WPM for nonfiction and 260 WPM for fiction (Brysbaert, Reference Brysbaert2019), and the reading rate of second or foreign language learners is much slower. Considering the role that reading fluency plays in reading comprehension, L2 learners should be provided with abundant opportunities to read (e.g., Beglar & Hunt, Reference Beglar and Hunt2014). Learners who read level-appropriate and intriguing materials read faster, comprehend more, enjoy more, and want to read more, entering the so-called “virtuous circle of the good reader” (Nuttall, Reference Nuttall1996).

3.2 Vocabulary

The significance of vocabulary in learning a foreign language cannot be overestimated. Research has shown that incidental vocabulary learning through reading occurs for both L1 and L2 learners. ER studies have suggested that graded readers can be an important source of vocabulary learning for L2 learners (e.g., Bourtorwick et al., Reference Boutorwick, Macalister and Elgort2019; Daskalovska, Reference Daskalovska, Ponniah and Venkatesan2018; Iwata, Reference Iwata2022; Jeon & Day, Reference Jeon and Day2016; Liu & Zhang, Reference Liu and Zhang2018; McQuillan, Reference McQuillan2020; Nakanishi, Reference Nakanishi2015; Pigada & Schmitt, Reference Pigada and Schmitt2006; Tabata-Sandom, Reference Tabata-Sandom2023). A meta-analysis of the effects of ER on English vocabulary learning showed that ER had a large effect (d = 1.32) for experimental versus control group comparison and a huge effect (d = 3.26) for pre-post comparison (Liu & Zhang, Reference Liu and Zhang2018). In another meta-analysis by Nakanishi (Reference Nakanishi2015), a large effect of ER on vocabulary (d = 1.25) was obtained for pre-post comparison. In Jeon and Day (Reference Jeon and Day2016), ER had a medium effect (d = 0.47) on vocabulary.

Considering the large effect of reading on vocabulary learning, researchers such as Krashen (Reference Krashen2004) advocated free voluntary reading as the main route for acquiring new vocabulary. When students do a lot of reading, they have multiple meaningful encounters over time with words. Their vocabulary size tends to increase, and they also learn new meanings or usages of words they already knew. Compared with the direct instruction of vocabulary, the incidental learning of vocabulary through reading has proven to be more efficient (e.g., McQuillan, Reference McQuillan2019). Pigada and Schmitt (Reference Pigada and Schmitt2006) listed a few reasons why it is very “attractive” to develop vocabulary knowledge through extensive reading (p. 2). First, ER is considered a pedagogically efficient approach because vocabulary learning and reading occur at the same time. Second, ER provides learners with the opportunity to meet words in their contexts of use. Third, learning vocabulary through ER can be pleasant and motivating, which, as a result, may facilitate learner autonomy.

As for factors affecting the vocabulary gains through ER, frequency of encounters (e.g., Pigada and Schmitt, Reference Pigada and Schmitt2006) and learners’ language proficiency (Park et al., Reference Park, Isaacs and Woodfield2018) have been demonstrated to play a role. The more a word is encountered, the higher the chance it is to be acquired. Previous studies have also endeavored to determine how many times a word needs to be encountered before learning occurs. As Nakanishi (Reference Nakanishi2015) argued, “One key to successful foreign language vocabulary acquisition is the opportunity to meet the same lexis repeatedly in communicative contexts; extensive reading can be of enormous assistance in this endeavor.” (p. 10). Of course, studies have also shown that some words are just more difficult to acquire. For example, G, a L2 French learner in Pigada and Schmitt (Reference Pigada and Schmitt2006) had difficulty learning words such as entendre ( “to hear”) and le radeau (“raft”) incidentally even after 20+ encounters.

Numerous empirical studies have been carried out to demonstrate the impact of ER on vocabulary acquisition. With sixty-one Taiwanese EFL learners as participants, Webb and Chang’s (Reference Webb and Chang2015) study found that vocabulary gains were 44.06% after reading ten graded readers and 36.66% after three months. Serrano (Reference Serrano2023) investigated English science vocabulary learning through reading nonfiction graded readers of scientific content in a one academic year long ER program. The participants were ninety-six Spanish primary school learners of English. The study showed that extensive reading and reading while listening produced an average immediate and long-term relative gain of 50.43% and 47.76% in vocabulary in Term 1. Tabata-Sandom (Reference Tabata-Sandom2023) showed that after reading online for one year, the average vocabulary size (measured by VocabularySize.com) of eleven advanced L2 learners increased from 7,081 to 8,481 word families, which is a 19.8 percent gain rate.

In some ER studies, vocabulary knowledge is equivalent to word meaning knowledge. However, it should be noted that there are different aspects of vocabulary knowledge. According to Nation (Reference Nation2001), there are twenty-six aspects of vocabulary knowledge categorized into three types: form, meaning, and use. Thus, scholars in the field suggested that more attention should be paid to other aspects of vocabulary knowledge and measure partial learning of the knowledge. For example, Pigada and Schmitt (Reference Pigada and Schmitt2006) examined how G, a 27-year-old L2 French learner, acquired 133 words (70 nouns and 63 verbs) while reading extensively. The study tested the learning of spelling, meaning, and use of 133 target words through a comparison of a pre-post vocabulary test. The graded readers G read were from the “Lectures CLE en Francais facile” collection (Level 1). The vocabulary lists of those readers ranged from 400 to 700 words. G read four graded readers in one month, which was 228 pages in total with approximately 30,000 words. G had no other French exposure apart from the graded readers. The results showed that there was a relatively strong enhancement in the spelling of the target words. G spelled 98 out of 266 (36.8 percent) words correctly in the pre-test. However, G spelled 159 out of 266 (59.8) words correctly in the post-test. This finding suggests that ER can be very beneficial for the spelling of French words, which are considered difficult to learn. This accords with Day and Swan’s claim of the “causal relationship” between foreign language reading and spelling (Reference Day and Bamford1998, p. 1). Next, the word meaning knowledge increased from 22 points out of 266 (8.3%) to 63 out of 266 (23.7%). The frequency of the exposure played a role in this study. When words were only encountered once, very little meaning uptake seemed to have occurred. At 2–3 exposures, there was a noticeable meaning acquisition for verbs, but this did not occur for nouns until 4–5 occurrences. By about 10+ exposures, there seemed to be a noticeable rise in the learning of meaning. As for use, the grammatical mastery of nouns (i.e., knowledge of appropriate articles) increased from 18 out of 140 (12.9%) to 60 out of 140 (42.9%); the grammatical knowledge of verbs (i.e., knowledge of appropriate prepositions) increased from 5 out of 126 (4%) to 26 out of 126 (20.6%). Thus, the acquisition of knowledge about which French articles accompany which nouns seem to be possible through reading. The knowledge of which prepositions accompany verbs, on the other hand, seemed to be acquired at a much slower rate.

Pigada and Schmitt (Reference Pigada and Schmitt2006) also looked at the 133 words individually and examined which aspect of vocabulary knowledge (i.e., spelling, meaning, or grammar) was learned about them. They found that sixty-six (49.6%) were enhanced in one type of word knowledge, thirteen (9.8%) in two types, and eight (6%) in all three types. Adding the results together, Pigada and Schmitt (Reference Pigada and Schmitt2006) found that some degree of learning was demonstrated for 87 out of 133 words, a pick-up rate of 64.5 percent, or 1 word out of every 1.5 words tested. Thus, it is safe to conclude that ER led to the enhancement of knowledge about the spelling, meaning, and grammatical knowledge of words.

Horst (Reference Horst2005) assessed the vocabulary gains of twenty-one adult immigrant ESL learners at a community center in Montreal, Canada. The average number of books read by the twenty-one learners was 10.52 (SD = 6.71) over a six-week period, which means that students on average read 1.75 books per week. To create a pre-test, Horst (Reference Horst2005) scanned the first twenty pages from each of the twelve graded readers to create a pre-reading baseline test of words. The scanned files of graded readers were analyzed using VocabyProfile, an online version of the Lexical Frequency Profiling software developed by Nation and Heatley (Reference Nation and Heatley1996). A 100-item pre-test with three rating options was prepared: No (I don’t know what this word means); Not sure (I have an idea about the meaning of this word, but I am not sure); and Yes (I know what this word means). As many as 50 words were chosen from a 1,001–2,000-word frequency list and 50 words not appearing on lists of 2,000 most common word families (called off-list words). The post-tests were individualized, which were based on the graded readers read by each student. The 100-item post-tests were identical to the pre-test in format but were made up entirely of words known to have occurred in the books read by the participants. The result demonstrated the acquisition of full or partial knowledge in 51.43 percent of previously unknown words.

Recent ER research also supported impressive gains in vocabulary learning through enhanced ER, such as reading while listening (Webb et al., Reference Webb, Newton and Chang2013; Webb & Chang, Reference Webb and Chang2015) and ER-plus approach (i.e, ER was supplemented with post-reading discussion in small groups, Boutorwick et al., Reference Boutorwick, Macalister and Elgort2019). Webb and Chang (Reference Webb and Chang2015) suggested that with the availability of audio files in graded readers, reading while listening rather than reading alone should be “the primary approach” to extensive reading today (p. 682). Boutorwick et al. (Reference Boutorwick, Macalister and Elgort2019) suggested that supplementing ER with discussion provided opportunities for further development of vocabulary knowledge.

In conclusion, the extensive body of research on ER strongly indicates its significant impact on vocabulary acquisition in language learning. Studies consistently demonstrate that ER facilitates incidental vocabulary learning, a process where learners gradually accumulate knowledge through repeated contextual encounters with words. This method has been proven effective not only in increasing the size of learners’ vocabulary but also in enhancing their understanding of word meanings, usage, and even spelling. Furthermore, the effects of vocabulary learning through ER has been observed to be enhanced when combining ER with other approaches. These findings underscore the versatility and efficacy of ER as a tool to foster vocabulary acquisition among learners.

3.3 Grammar

Not surprisingly, ER contributes to the learning of grammatical structures as has been demonstrated in both quantitative and qualitative studies (e.g., Aka, Reference Aka2019, Reference Aka2020; Lee et al., Reference Lee, Schallert and Kim2015; Nakano, Reference Nakano2023). While reading extensively with ease, students encounter a variety of grammatical patterns in contexts. The repeated exposure to grammatical structures from reading is cumulatively registered in the implicit learning system and as a result leads to incidental learning of grammar knowledge (Grabe, Reference Grabe2009). Research has shown that ER may play a more effective role in improving grammar knowledge than other methods such as explicit grammar instruction (e.g., Aka, Reference Aka2019) or translation (Lee et al., Reference Lee, Schallert and Kim2015).

Adopting an experimental-control group design, Aka (Reference Aka2019) implemented ER among a group of 200 high school EFL learners in Japan. The control group (n = 205) had six English classes a week: 3 hours of intensive reading classes, 2 hours of grammar classes, and 1 hour of listening class. The ER group took the same number of English classes, but instead of two hours of grammar classes, this group took two hours of extensive reading classes. Students in the control group learned one grammar item each week and worked on grammar exercises. Students in the ER group were asked to select ER books at the i-1 level from a library of 3,000 graded readers. Thus, the only difference between the two groups was whether they had sixty hours of grammar instruction or ER over a course of one year. At the beginning of the experiment, the two groups did not significantly differ in their grammar and vocabulary knowledge measured by a proficiency test called BACE, however, the ER group performed significantly better in the grammar and vocabulary section of the test compared to the control group after one year. In a similar vein, Lee et al. (Reference Lee, Schallert and Kim2015) compared the effects of two approaches, ER and translation, on knowledge of general grammar and specific syntactic features (i.e., articles and prepositions) among 124 middle school EFL learners in South Korea. The results showed that ER produced positive outcomes on grammar measures for high-level students.

A recent study also investigated the extent to which different ways of presenting grammatical information in graded readers influenced the incidental learning of grammatical knowledge (Nakano, Reference Nakano2023). The reading materials were two passages from JGR SAKURA, a website for L2 Japanese extensive reading that provides Japanese graded readers as well as one online Vocabulary Level Test for L2 Japanese. The study provided both graded readers with parts of speech being color-coded and normal texts for L2 learners at the elementary proficiency level. Compared to those reading normal texts, the participants who used the form-focused text (i.e., color-coded) tended to obtain higher scores in tests that assessed function word recognition and the relationship between modifiers and modified words. The results need to be interpreted with caution because only two texts were read in the study.

Frequency of exposure also plays a role in the incidental learning of grammar knowledge. Aka (Reference Aka2020) investigated the effects of reading on the incidental learning of a specific grammatical feature – to-infinitives used as nouns among 157 Japanese high school EFL learners. The experimental group (n = 74) read five passages consisting of a total of forty sentences that include to-infinitives used as nouns, while the control group (n = 83) also read five reading passages, but with only ten sentences consisting of to-infinitives used as nouns.  The study showed that the experimental group participants noticed and learned about to-infinitives used as nouns. The study provided evidence that frequency of exposure contributed to the incidental learning of grammar.

In conclusion, the evidence from both quantitative and qualitative studies supports the notion that ER plays a crucial role in the incidental learning of grammatical structures for language learners. Through ER, students are repeatedly exposed to a variety of grammatical patterns in context, facilitating their absorption and understanding of these structures in a way that appears to be more effective than traditional methods like explicit grammar instruction or translation. These findings highlight the value of incorporating ER into language classrooms, not only for vocabulary development but also for enhancing students’ grammatical competence more naturally and effectively.

3.4 Writing

A good reader is also a good writer. Reading more is connected to better writing skills in both first (e.g., Sun et al., Reference Sun, Yang and He2016) and second language (e.g., Park, Reference Park2016). Empirical studies have shown that ER groups performed significantly better in key areas of writing compared to control groups (see Lee & Schallert, Reference Lee and Schallert2016; Mermelstein, Reference Mermelstein2015). This body of research examines the effects of ER on different aspects of writing, such as task achievement, coherence and cohesion, lexical resource, and grammatical range and accuracy. For example, Mermelstein’s (Reference Mermelstein2015) study investigated the extent to which an enhanced ER program improved the writing abilities of 211 third-year college EFL learners in Taiwan, China. ER was implemented as a sustained silent reading (SSR) activity, ranging from fifteen to twenty minutes. As many as 600 graded readers at Level 1 to Level 6 from the Oxford Bookworms and the Penguin Readers were available for the participants. The writing assignment was a descriptive paragraph writing, with “Your Past Summer Vacation” and “Your Future Summer Vacation” as topics for the pre- versus post-tests. The study showed that the ER group outperformed the control group in vocabulary, language use, spelling/mechanics, and fluency of writing.

A relationship between the amount of ER and writing achievement has also been established in research (e.g., Odo, Reference Odo2020; Sakurai, Reference Sakurai2017). For example, Sakurai (Reference Sakurai2017) investigated the relationship between the amount of extensive reading and the writing performance among 157 first and second-year EFL university students in an English language program at a private university in Japan. The students were taking English courses at different levels. ER was a component in some of the courses. Students needed to read 36,000 words and ER constituted 20 percent of the final grade in those courses. Some students were enrolled in a course that required them to read a minimum of 75,000 words. Students selected books from a library with over 12,000 ER books, read outside the classroom, and took quizzes on MReader. Students read 66,242 words on average. Based on the reading amount, the students were divided into four groups: Group 1: < 36,000 words; Group 2: 36,000–71,999 words; Group 3: 72,000–107,999 words; and Group 4: >108,000 words. The assessment of the writing was a letter-writing task. The participants were asked to write a letter of 150 words to a non-Japanese friend abroad about recent news in Japan and explain why Japanese people were interested in it. The grading rubric included task achievement, coherence and cohesion, lexical resource, and grammatical range and accuracy (see Appendix B in Sakurai, Reference Sakurai2017, pp. 160–161). The results showed that the amount of reading was significantly correlated with the writing score total at 0.212 (p < 0.01). As for the four components of the writing rubric, the amount of ER was significantly correlated with lexical resource at 0.294 (p < 0.001) and grammatical range and accuracy at 0.246 (p < 0.01). In terms of the four groups, the group read more than 108,000 statistically outperformed the other three groups in lexical resource (p < 0.001) and grammatical range and accuracy (p < 0.01).

Additionally, the difficulty level of reading materials may influence writing quality. Odo (Reference Odo2020) revealed that more challenging ER materials were associated with greater writing class grade performance. However, there is a need for more studies to be conducted.

As for the genres of the writing, the studies have examined the effects of ER on letter writing (e.g., Sakurai, Reference Sakurai2017), descriptive writing (Mermelstein, Reference Mermelstein2015), book reports (e.g., Kim & Ro, Reference Kim and Ro2023; Sun, Reference Sun2020), and academic writing (e.g., Park, Reference Park2016).

To conclude, current research has shown that the large amount of language input, together with opportunities to practice writing, contributes to different aspects of L2 writing ability in a variety of genres.

3.5 Speaking

ER might promote speaking abilities in three ways. First, students learn oral expressions from ER books and then apply them in their speech. Many graded readers include dialogues, which demonstrates to learners how spoken language is produced. For example, in Zhou and Day (Reference Zhou and Day2021), EAP students mentioned using expressions learned from ER in their speaking. Second, ER, especially audio-assisted ER, has been shown to enhance students’ pronunciation. Kirchhoff and Mision (Reference Kirchhoff and Mision2022) found that students enjoyed the reading while listening program (RWL) and felt it improved their pronunciation, prosody, and intonation. Third, ER-related activities, particularly speaking exercises, may enhance students’ speaking abilities. L2 Chinese learners in Zhou and Day (Reference Zhou and Day2023) expressed that ER itself did not directly improve their speaking. However, their involvement in ER activities, such as summarizing stories they read to each other, teaching vocabulary, and describing drawings, significantly improved their speaking abilities.

3.6 Reading Attitude

Alexandar and Filler (Reference Alexander and Filler1976) defined reading attitude as “a system of feelings related to reading which causes the learner to approach or avoid a reading situation” (p. 1). Research has consistently shown that ER contributed to positive reading attitudes in an L2 (e.g., Habib & Watkins, Reference Habib and Watkins2023). After reviewing a list of reading attitude studies, Yamashita (Reference Yamashita2004) summarized that reading attitude contains three components: cognitive (personal, evaluative beliefs), affective (feelings and emotions), and conative (action readiness and behavioral intentions). Day and Bamford (Reference Day and Bamford1998) claimed that four factors might affect L2 reading attitude:

• L1 reading attitude

• previous experience with learning to read other second languages

• attitudes toward the L2, culture and people

• the L2 classroom environment such as teachers, classmates, and ongoing experience in L2 reading.

Empirically, Yamashita (Reference Yamashita2004) investigated the relationship between L1(Japanese) and L2 (English) reading attitudes and ER performance among fifty-nine Japanese EFL university students. A factorial analysis revealed four components of reading attitude: comfort (i.e., positive feeling), anxiety (negative feeling), value (i.e., values of reading), and self-perception (i.e., students’ perceptions of themselves as readers). It was found that values of reading in L1 and L2 are significantly correlated (r = 0.629). Anxiety in reading is higher in L2 than in L1, comfort in reading is higher in L1 than L2, the value that the students attached to reading does not differ between L1 and L2, and self-perception as a reader is more positive in L1 than in L2. Among the two affective variables, anxiety and comfort, only comfort was significantly correlated with ER performance measured by the number of pages read. This indicates that positive feelings facilitated ER, highlighting the role of positive feelings in enhancing reading attitude. As the author claimed, experiencing a positive feeling is more motivational than not experiencing a negative feeling (Yamashita, Reference Yamashita2004).

The relationship between ER and reading attitude seems to be a reciprocal one. Zhou and Day (Reference Zhou and Day2021) revealed that fifty-seven EAP students’ reading attitude was significantly improved after an online ER program lasting for ten to twelve weeks. Mohd Asraf and Ahmad (Reference Mohd Asraf and Ahmad2003) showed that students in rural schools in Malaysia developed positive attitudes toward reading in English after four months of Guided Extensive Reading.

L2 learners, including advanced ones, often experience feelings of anxiety, fear, and reluctance toward reading in a foreign or second language, as reported in studies like Tabata-Sandom (Reference Tabata-Sandom2023). Comfort and enjoyment while reading in their L2 are less common among these learners, often due to various factors such as the difficulty of the reading materials or reading primarily to learn vocabulary and grammar (e.g., Ro, Reference Ro2013). ER, as an innovative approach to language teaching, offers L2 learners the opportunity to enjoy reading and develop a habit of it.

3.7 Reading Motivation

Motivation plays an important role in successful foreign or second language reading. Day and Bamford (Reference Day and Bamford1998) defined motivation as “what makes people do (or not do) something” (p. 27). As we have discussed in the previous section, reading attitude is about positive or negative feelings toward reading. Motivation, however, goes a step further by serving as a prerequisite for actual reading behavior. It directly or indirectly influences the amount of reading and the time devoted to ER, as suggested by Mori (Reference Mori2002). Research on motivation and ER has consistently shown a strong positive relationship between the two (Robb & Ewert, Reference Robb and Ewert2024).

Day and Bamford explained the motivation to read in an L2 through the Expectancy Value model (p. 28). The Expectancy Value Model is composed of four variables: (a) materials, (b) reading ability in the L2, (c) attitude toward reading in the L2, and (d) sociocultural environment. Day and Bamford claimed that (a) materials and (c) attitude toward reading in the L2 are the critical components of reading motivation.

Empirical research has provided evidence for Day and Bamford’s Expectancy Value model (e.g., Tabata-Sandom, Reference Tabata-Sandom2023; Takase, Reference Takase2007). For example, studies have reported that providing appropriate reading materials was a crucial factor in motivating L2 learners to read (Bui & Macalister, Reference Bui and Macalister2021; Takase, Reference Takase2007). The books’ intriguing contents motivated students to form the reading habit (Bui & Macalister, Reference Bui and Macalister2021).

Noticing an improvement in language abilities will motivate students to read. For example, students in Bui and Macalister (Reference Bui and Macalister2021) reported that reading online promoted their reading fluency and vocabulary knowledge, thus this observed improvement in their reading abilities was an incentive for them to maintain their reading habits.

Takase (Reference Takase2007) identified a list of components of L1 and L2 reading motivation among a group of female Japanese high school EFL learners. Their parents’ involvement in and family attitudes toward reading was one of the components. This demonstrates that sociocultural factors such as parents, teachers, and classmates all play a role in motivating students to read or not.

Zhou and Day (Reference Zhou and Day2023) showed that positive attitudes toward L2 reading (e.g., confidence) may motivate students to continue reading and taking Chinese classes. It is safe to say that motivation to read is influenced by reading materials, L2 reading abilities, contextual factors, as well as attitudes toward L2 reading.

It is worth noting that motivation for ER is not static, but complex and dynamic (de Burgh-Hirabe & Feryok, Reference de Burgh-Hirabe and Feryok2013). It is dynamic because the motivation for ER can increase or decrease. For example, in de Burgh-Hirabe and Feryok (Reference de Burgh-Hirabe and Feryok2013), nine L2 Japanese learners from two high schools in a New Zealand city were encouraged to read extensively outside class for five to seven months. Motivation for ER changed for seven of the nine participants. The motivation of four students increased, three students decreased, and two students remained stable. Research has also shown that readers may start to read with extrinsic motivation, which can be transferred to intrinsic motivation when reading tasks are intriguing (e.g., Demirci, Reference Demirci2019).

Motivation is also complex (e.g., de Burgh-Hirabe & Feryok, Reference de Burgh-Hirabe and Feryok2013; de Lozier, Reference de Lozier2019; Ro, Reference Ro2018; Robb & Ewert, Reference Robb and Ewert2024). Diverse internal and external factors may enhance or hinder learners’ commitment to ER (Robb & Ewert, Reference Robb and Ewert2024). de Burgh-Hirabe and Feryok’s study (Reference de Burgh-Hirabe and Feryok2013) showed motivation to read in L2 Japanese was influenced by multiple factors, including students’ attitudes about Japanese language and culture, their beliefs about L2 learning, their perceived success in ER, their workload at school, their social relationships and so on. Motivation to read may also vary among learners with different proficiency levels, for example, high- and intermediate-level learners versus low-level readers (de Lozier, Reference de Lozier2019). The former group performed better and enjoyed reading more under intrinsic conditions while the latter benefited more from extrinsic motivational requirements.

Research has revealed that individual readers can apply regulation strategies to increase their motivation to read (e.g., Arnold, Reference Arnold2009; de Burgh-Hirabe & Feryok, Reference de Burgh-Hirabe and Feryok2013; Li et al., Reference Li, Majumdar, Chen, Yang and Ogata2023). This ability is called self-regulation, the self-directive processes and self-beliefs that enable learners to transform mental abilities into academic performance skills (Zimmerman, Reference Zimmerman2008, p. 166). Two examples are learners in de Burgh-Hirabe and Feryok’s study (Reference de Burgh-Hirabe and Feryok2013) who regulated the challenges posed by the books (e.g., reading challenging books) as well as the environment (e.g., allocating time for ER). Li et al. (Reference Li, Majumdar, Chen, Yang and Ogata2023) showed that students with high self-directed learning abilities significantly increased their reading amount and days than those with low self-directed learning abilities while doing online ER on BookRoll, a digital teaching material distribution system developed by Kyoto University.

As has been discussed, motivation decides whether students want to read, how much they read, and how long they spend on reading. The experience of reading extensively in a foreign language, on the other hand, can promote reading motivation. Ro (Reference Ro2013) examined the extent to which ER motivated an L2 reader Liza (pseudonym), a twenty-eight-year-old Korean female, in twenty-four extensive reading sessions over an eight-week period. Liza’s motivation was enhanced through ER due to the influence of the following factors (comfort or ease, enjoyment, satisfaction, convenience or accessibility, and usefulness). Liza felt comfort or ease in comprehension from exposure to repeated use of the same words or phrases, no pressure for reading, and familiarity with the background and storyline of the books. Another factor that increased reading motivation was enjoyment experienced while reading (i.e., enjoyment in reading comics and enjoyment in reading the colloquial expressions). Liza also experienced satisfaction after finishing reading English books, which motivated her to purchase more L2 comics and read more.

In language classrooms, some readers may not have intrinsic motivation for ER when they first get into contact with it. However, extrinsic motivation (e.g., easy to get credits) could be transformed into intrinsic motivation as has been demonstrated in some studies (e.g., Arai, Reference Arai2022; Mori, Reference Mori2015). The phenomenon is supported by the concept of emergent motivation (Csikszentmihalyi et al., Reference Csikszentmihalyi, Abuhamdeh, Nakamura, Elliot and Dweck2005). Gamification features like leaderboards, prizes, progress bars, star system, avatar builder, badges, raz-rockets, and certificates can also be incorporated into the design of ER programs to enhance motivation to read, especially among young learners (e.g., Grade 2 to 5 L1 Korean EFL learners in Jun, Reference Jun2018; Grade 5 to 6 primary school students in Iraq, Bala, Reference Bala2022). Book review activity through Bibliobattles (a social book review game) combines silent reading and public sharing of books, which also enhances motivation to read (Maclauchlan, Reference Maclauchlan2018). Robb and Ewert (Reference Robb and Ewert2024) also explored additional strategies and incentives to motivate readers, such as reading marathons, book sharing, and quizzes, among others. Teachers should also pay attention to the fluctuation of students’ motivation toward ER (Mikami, Reference Mikami2017). Without maintaining and actively enhancing students’ motivation to read, it will be very difficult to keep students engaged in ER over an extended period of time.

In summary, the role of motivation in ER is both critical and multifaceted, influencing learners’ willingness to read, the amount of reading they undertake, and the duration of their engagement with ER. Empirical research underscores that motivation for ER is not static but dynamic and complex, subject to changes and influenced by a myriad of factors, including material appropriateness, reading ability, attitude toward L2 reading, and the sociocultural environment. Studies have shown that motivation can evolve from extrinsic to intrinsic, especially when the reading material is engaging. It is important for language teachers to recognize and address the fluctuating nature of motivation to ensure sustained engagement in ER, thereby maximizing its benefits.

3.8 Reading Habit

Reading habit has been a topic of interest in many ER studies. It was defined as “how often, how well, and what adults like to read” (Scales & Rhee, Reference Scales and Rhee2001, p. 178). In Rodrigo et al.’s (Reference Rodrigo, Greenberg and Segal2014) study, it was operationalized as how frequently the participants read novels, whether they read the entire book, and whether they engage in literacy-related activities such as visiting bookstores or libraries. Positive reading attitude is an important factor in the development of a reading habit. Since ER has been shown to enhance reading attitudes, it also contributes to the forming of a reading habit.

Rodrigo et al. (Reference Rodrigo, Greenberg and Segal2014) investigated the effects of two reading interventions, one ER group and another non-ER group, on the reading habits of 181 adults with low literacy skills. The study showed that the participants in the ER group developed more of an ability to finish reading a whole book compared to the participants in the non-ER group. As for bookstore and library visits, the ER group and the non-ER group did not differ before the treatment. However, after the treatment, the ER group visited bookstores and libraries statistically more often than participants in the non-ER group. As expected, the ER group read statistically more books compared to the non-ER group. Furthermore, what is worth noting is that participants in the ER group, six months after treatment, were still reading more books than those in the non-ER group. Thus, it was concluded that the ER intervention was more effective in promoting a reading habit (Rodrigo et al., Reference Rodrigo, Greenberg and Segal2014).

Setting a reading requirement such as how many words, pages, or books students need to read has been shown to help the formation of a reading habit. For example, Zhou and Day (Reference Zhou and Day2021) required EAP students in an English language institute in an American university to read 10,000 to 12,000 words per week. One interviewee said “Until I really try reading it, so I say, this is good, so I made a habit to read it” and he “reads every week” (p. 14). Teachers’ guidance and scaffolding also promote the forming of a reading habit. Tabata-Sandom (Reference Tabata-Sandom2023) regularly sent newsletters to her advanced L2 learners to recommend books and encourage each participant. This “soft enforcement” helped the participants to commit to the ER program.

In conclusion, the development of a reading habit is a key focus in ER, with studies indicating that ER significantly contributes to the formation of a reading habit. The research findings so far collectively underscore the value of ER in not just improving reading skills but also in instilling a lasting appreciation and practice of reading.

3.9 Flow Experience

Flow theory emerged from the work of Csikszentmihalyi (Reference Csikszentmihalyi, Csikszentmihalyi and Csikszentmihalyi1988) researching humans’ optimal or most enjoyable experiences. Engeser and Schiepe-Tiska (Reference Engeser, Shiepe-Tiska and Engeser2012) defined flow as a perceived state in which “an individual is completely immersed in an activity without reflective self-consciousness but with a deep sense of control” (p. 1). Analysis from a variety of people in different professions and cultures revealed similar explanations of life’s most enjoyable experiences, that is, an intense focus on a task. When in the flow state, people focus their intention completely on what they are doing. Their action and consciousness are being sufficiently merged that they lose their self-consciousness (Nakamura & Csikszentmihalyi, Reference Nakamura, Csikszentmihalyi, Lopez and Snyder2009).

According to Csikszentmihalyi (Reference Cohen1988), conditions for a flow experience included clear goals, feedback, skills matching challenges, an environment to concentrate, and an element to control. Kirchhoff (Reference Kirchhoff2013, p. 199) mentioned that the five conditions that allow for flow experience to occur are quite similar to the principles and practices of ER (see Table 3).

It is hard to become immersed in an activity when one does not know what needs to be done (i.e., clear goals) and how well one is doing (i.e., immediate feedback). ER programs usually set clear goals for students. For example, L2 Chinese learners in Zhou and Day (Reference Zhou and Day2023) were required to read one graded reader per week. Advanced, post-tertiary L2 English learners in Tabata-Sandom (Reference Tabata-Sandom2023) agreed to read fifteen minutes per day, and that reading amount is “the contract” (p. 172). Day and Bamford (Reference Day and Bamford1998) recommended students in ER programs read one book per week. Thus, it seems that it would be beneficial to set up clear reading goals in ER programs. ER also gave students real-time feelings as feedback so it encouraged them to read consistently for its own sake (Fongpaiboon, Reference Fongpaiboon2017).

People also reported focused concentration when involved in enjoyable activities. Attention was reported to be completely immersed in the activity at hand, so that the “merging of activity and awareness” is a typical feature of the flow experience (Csikszentmihalyi, Reference Csikszentmihalyi, Csikszentmihalyi and Csikszentmihalyi1988, p. 32). One reader in Tabata-Sandom (Reference Tabata-Sandom2023) said, “When a story is interesting, one hour feels like a second, even if it’s in English” (p. 172). Because of the deep concentration on the activity at hand, the results of flow experience include temporarily losing the awareness of self, forgetting problems in life or work, lacking self-consciousness (Kirchhoff, Reference Kirchhoff2013) and even experiencing a “transcendence of self,” caused by the unusually high involvement in an action (Csikszentmihalyi, Reference Csikszentmihalyi, Csikszentmihalyi and Csikszentmihalyi1988, p. 33).

The universal precondition for flow is that a person “should perceive that there is something for him or her to do, and that he or she is capable of doing it” (Csikszentmihalyi, 1988, p. 30). In other words, flow or optimal experience requires a balance between the challenges and the skills a person brings to it. Csikszentmihalyi (Reference Csikszentmihalyi, Csikszentmihalyi and Csikszentmihalyi1988) gave an example of playing tennis. When a tennis player plays tennis and feels enjoyment, he/she wants to play more. The more such individuals play, the better their skills will be. If they continue to play against opponents of the same level as before, they will feel bored. To return to flow and replicate the enjoyment, they have to play with stronger opponents. Thus, to maintain the flow, one must increase the complexity of the activity by “developing new skills and taking on new challenges” (Kirchhoff, Reference Kirchhoff2013, p. 30). This dynamic and spiraling complexity is what makes flow a process of “discovering something new” (p. 30).

Flow pushes people to stretch themselves, take on new challenges, and sharpen their skills. Participants in Tabata-Sandom (Reference Tabata-Sandom2023) reported flow experience when they started reading higher-level, longer books. Arai (Reference Arai2022) investigated the relationship between perceived book difficulty and flow experience. The survey results showed that the participants reading “i plus 1” books had higher total scores on the flow scale than those who read “i minus 1” ones. The study suggested that many participants found flow in their reading and that ER was a “flow-generating” activity (p. 16). This finding is especially relevant to book selection. Some students may tend to read and stay at easy and low levels. However, they could be encouraged to select books that match their reading abilities.

Empirical research has also been conducted on the flow experience in ER programs. For example, Kirchhoff (Reference Kirchhoff2013) investigated the occurrences of flow experience from two groups of Japanese college students (seventy-two in total) in extensive reading classes. The extensive reading class met once a week for ninety minutes and continued for fifteen weeks. Every class included thirty minutes of silent reading time and other activities such as repeated reading tasks or discussion about books with classmates. Flow experience was mentioned in relation to book selection, with the purpose of encouraging students to select books that are at the readers’ levels so that the books are not too boring or too challenging. Students were also encouraged to read at least an hour outside class. The questionnaires asked for frequency of flow-like experiences, descriptions of conditions that enabled flow, reading speed, amount of reading accomplished, L1 reading flow experience, and specific elements of flow experiences. The results revealed that the participants reported flow-like experiences when reading graded readers. The study suggested that teachers can facilitate the flow experience by providing books that are interesting to students and at the students’ reading levels, and by encouraging students to read in a calm and relaxing environment.

Fongpaiboon (Reference Fongpaiboon2017) investigated the flow experience of sixty-eight Thai undergraduate students from doing ER for one semester. The study explored both the external and internal conditions for flow experience to occur. The results revealed that a quiet, calm, and relaxing environment, being able to select reading materials, and intriguing reading content were the top three ranked external conditions to enable flow experience. The interview data showed that the self-selection of ER materials helped students visualize or imagine while reading the stories and enabled flow experience. For example, one of the interviewees said:

To conclude, as Grabe stated, the concept of flow provides a strong rationale for promoting ER, both in and out of the classroom (Reference Grabe2009). The characteristics of ER of being able to read intriguing, level-appropriate materials for general understanding and enjoyment encouraged participants to experience flow through the power of making reading decisions by readers.

4.1 English

In this section, I mainly present descriptive statistics of the number of ER studies conducted in EFL/ESL contexts from 2018 to 2023. I will not describe individual studies in EFL/ESL contexts because many examples have been provided in Section 3. The data source is from the Extensive Reading Foundation’s annotated bibliography of works on ER (https://bib.erfoundation.org). The main reason is that the bibliography is a comprehensive collection of the ER studies published in different journals, including Reading in a Foreign Language, Journal of Extensive Reading, The Reading Matrix, and other international and local journals. The annotated bibliography also included dissertations, MA theses and discussion pieces on ER. The focus of this analysis primarily rests on ER studies published in English. This is due to limitations in my language proficiency, time, and available space, which may preclude the comprehensive inclusion of studies published in other languages.

Day and Bamford (Reference Day and Bamford1998) published their seminal book on ER in 1998, thus papers published in and after 1998 were perceived to reflect the nature of ER and followed the top ten ER principles to a different extent. Thus, I searched and downloaded all the studies collected in the database published in and after 1998. The search resulted in 644 studies. Due to the limited space, this section only reported the data for the last five years, from 2018 to 2023. I hope readers can gain an understanding of the most recent trends in ER research and practices.

As many as 175 ER studies were published from 2018 to 2023. An initial reading of the papers showed that thirty-three studies were not related to ER (e.g., on extensive listening, vocabulary learning through reading, reading models review). Thus, those studies were not included in this analysis. Thirty-six studies from 2018 to 2023 were related to ER (e.g., discussion of ER implementation issues, Renandya et al., Reference Renandya, Ivone and Hidayati2021; ER website review, Alzahrani, Reference Alzahrani2022), but they are not empirical studies. Thus, those studies were not included in the analysis.

Table 4 presents the number of empirical ER studies conducted from 2018 to 2023. Around 106 empirical studies on ER were published from 2018 to 2023, among which eighty-eight (83.02%) were conducted in EFL contexts, five studies (4.72%) in ESL contexts, and three studies did not specify whether it was an ESL or EFL context. Only one study was conducted in French as a foreign language, Chinese as a foreign language, L2 Spanish, L2 Italian, and Norwegian as an additional language, respectively. Four studies were conducted in L2 Japanese. Thus, we can conclude that the majority of ER studies were conducted in EFL contexts.

The studies conducted in EFL/ESL contexts investigated a variety of topics in ER, including but not limited to attitude (e.g., Birketveit et al., Reference Birketveit, Rimmereide, Bader and Fisher2018; Endris, Reference Endris2018; Park, Reference Park2020), motivation (e.g., Al Damen, Reference Al Damen2018; de Lozier, Reference de Lozier2019; Demirci, Reference Demirci2019; Tusmagambet, Reference Tusmagambet2020), reading fluency (Tragant Mestres et al., Reference Tragant Mestres, Llanes Baró and Pinyana Garriga2019; Tusmagambet, Reference Tusmagambet2020), vocabulary (Aliyar & Peters, Reference Aliyar and Peters2022; Bourtorwick et al., Reference Boutorwick, Macalister and Elgort2019; Sakurai, Reference Sakurai2023; Stoeckel et al., Reference Stoeckel, McLean and Nation2021), reading comprehension (Lyddon & Kramer, Reference Lyddon, Kramer, Meuiner, Vyver, Bradley and Thouësny2019; Shimono, Reference Shimono2023), self-efficacy (McLean & Poulshock, Reference McLean and Poulshock2018), reading amount (Jun, Reference Jun2018; McLean & Poulshock, Reference McLean and Poulshock2018) and so on.

The studies conducted in EFL contexts were carried out in a variety of countries and among learners speaking different L1s, such as Japanese (Arai, Reference Arai2022; Klassen & Allan, Reference Klassen and Allan2019; Klassen & Green, Reference Klassen and Green2019; Kramer & McLean, Reference Kramer and McLean2019; Sakurai, Reference Sakurai2023; Shimono, Reference Shimono2023), Amharic (Endris, Reference Endris2018), Korean (Ro, Reference Ro2018), Mandarin Chinese (Shih et al., Reference Shih, Chern and Reynolds2018), Arabic (Abdulrahman & Kara, Reference Abdulrahman and Kara2023; Al Damen, Reference Al Damen2018), Indonesian (Zulfariati, Reference Zulfariati2023), Emirati (Demirci, Reference Demirci2019), Kazakh (Tusmagambet, Reference Tusmagambet2020), Norwegian (Birketveit et al., Reference Birketveit, Rimmereide, Bader and Fisher2018), and so on.

4.2 Chinese

Chinese is a logographic writing system and reading in Chinese may cause anxiety, especially among readers whose L1 is an alphabetical language (Zhou, Reference Zhou2017). Chinese differ from English in many ways. First, the basic graphic form in Chinese is the character. Each character corresponds to a syllable and carries meaning. Chinese characters function as the basic units in Chinese reading (e.g., Zhou, Reference Zhou2023). Each character is composed of strokes, which are combined to form radicals. There are two types of radicals in Chinese, semantic and phonetic radicals. The former provides information on the meaning of the character while the latter provides hints to its pronunciation. L1 and L2 Chinese reading research has shown that radical knowledge increases with years of language learning and there is a strong relationship between radical knowledge and character recognition (e.g., Shen & Ke, Reference Shen and Ke2007; Zhou, Reference Zhou2023). Second, Chinese employs compounding as an effective and productive way of word formation (Zhou, Reference Zhou2021). The compounding process allows two or even three morphemes (Chinese characters) to form a compound word. According to the Modern Chinese Frequency Dictionary, disyllabic words (e.g., two-charatcer/morpheme words) compose 74 percent of the total corpus of commonly used words (cf. Shen & Ke, Reference Shen and Ke2007). The two characters in a compound word form a quasi-syntactic relationship with each other. Yip (Reference Yip2000) identified five types of relationships commonly found in Chinese disyllabic words: juxtopositional, modificational, governmental, predicational, and complemental. Research has shown that morphological awareness directly contributed to vocabulary knowledge in Chinese reading and indirectly contributed to Chinese reading through the mediation of vocabulary knowledge (e.g., Zhou, Reference Zhou2021). Third, unlike English which is an inflectional language, there are few explicit syntactic or grammatical markers in Chinese (e.g., Zhou, Reference Zhou2022). As a result, Chinese readers rely on their syntactic knowledge such as word order to solicit information about tense, parts of speech, and so on. Taking the features of the Chinese language into consideration, researchers called for providing more opportunities for students to read extensively in Chinese (e.g., Zhou, Reference Zhou2018).

Compared to studies in EFL and ESL contexts, there is a scarcity of research on ER in L2 Chinese, for example, Chinese as a foreign language (CFL) or Chinese as a second language, (CSL) contexts. This does not mean that ER programs have not been set up in L2 Chinese contexts. When I was a PhD student at the University of Hawai’i at Manoa, the Chinese flagship housed in the East Asian Language and Literatures Department had an ER library, and students learning Chinese were encouraged to read extensively. A recent publication by me and Dr. Richard Day reported the establishment of an ER program in a CFL context. The ER program was established in an American liberal arts college.

An important step in establishing an ER program was to build an ER library (Day & Bamford, Reference Day and Bamford2002). An ER library with approximately 200 books was set up for the Chinese ER program. The books were all graded readers, mainly from the Chinese Breeze graded readers series (Liu & Chu, Reference Liu and Chu2008). The books were labeled into three levels according to the number of headwords of each book: Level S (150 headwords), Level 1 (300 headwords), and Level 2 (500 headwords).

The program was run from 2018 to 2022 and went through many changes. For example, ER was changed to an online format during the pandemic and the reading amount was also adjusted based on students’ feedback. Students were required to read one book per week, as suggested by Day and Bamford (Reference Day and Bamford2002). A total of 5 percent of the final grade was assigned to ER. Students were required to read both in class and outside of the class. Class time was also allocated to ER activities.

Zhou and Day (Reference Zhou and Day2023) mainly investigated the effects of ER on L2 Chinese reading attitude, students’ perceptions of language abilities being improved, and their views of ER activities.

The factorial analysis of the reading attitude survey showed a five-factor structure: confidence, enjoyment, interest, practical value, and devotion. It was found that L2 Chinese learners differed in their reading attitude before and after reading extensively for one semester. Confidence and devotion were two reading attitude components being improved significantly. The effect sizes of confidence d = 0.66 and devotion d = 0.35 indicated that L2 Chinese learners had 0.66 and 0.35 standard deviations of more confidence in reading in Chinese and devotion to learning the Chinese language after reading ten ER books for one semester. The end-of-the-semester final reflection showed that 86 percent of the learners enjoyed ER. They reported that the reading materials were interesting, fun, and out of the ordinary. Moreover, ER made them more confident, and they learned about Chinese culture through reading.

As for the language abilities perceived to have been improved, the students reported that reading speed (twenty-three times), reading comprehension (twenty-one times), vocabulary (twenty times), grammar (eighteen times), writing (nine times), character and word inferencing (seven times), character recognition (four times), listening (three times), and speaking (three times) were all improved. The number in the parenthesis indicated the frequency of that language ability mentioned by the forty-one participants. Two language abilities are specifically related to learning Chinese: character and word inferencing and character recognition. Participants noted that they became more capable of dealing with unknown characters by using contextual clues or simply skipping unknown characters.

L2 Chinese learners in Zhou and Day (Reference Zhou and Day2023) were asked to complete ER activities, which were adapted from Bamford and Day (Reference Bamford and Day2004). Some of the activities were more traditional ones such as the Instant Book Report, while others were more creative ones, such as Gifts (to give main characters gifts) and My Story (Students create their own stories). Please see Zhou and Day (Reference Zhou2023, p. 229, Table 3) for the complete list of the ER activities and their descriptions.

One of the activities in The Story and Drawing asked students to fill in the basic information about the stories they read, then to draw pictures based on the stories, to write briefly about the pictures and what happened in the story before and after the picture, and express their opinions of the stories. Figures 1 and 2 are examples of one student’s work for the activity The Story and Drawing. This student read a Level 1 book. The name of the book is 错错错 (Wrong, Wrong, Wrong). It is from the Chinese Breeze graded readers series by Liu and Chu (Reference Liu and Chu2008) published by Beijing University Press. This student thought this book was very interesting (5 out of 5). As for the difficulty level, 4 was selected, so it seemed that the book was challenging for this student. It took the student two hours to complete reading this book. As for the reasons why this student liked the book, it was stated, “I really like this book, because it is different from all the Chinese books I read before. It is the first detective story I read in Chinese, and I would like to read more stories of this genre.”

Figure 1 ER activity – The Story and Drawing – Part 1 book report.

Figure 2 A student’s drawing of the story Cuo Cuo Cuo and a brief explanation of the drawing – Part 2.

Note. The description of the drawing in English: Officer Li Liang looks at a dead woman. It seems like she committed suicide. It appears she died from drinking cyanide. Also, there is a letter written next to her, and Officer Li writes down in his notebook everything he sees and hears.

Here is another example of a story read by one student (see Figure 3). The name of the book is Shennong Tasting a Hundred Herbs. Shennong, also known as the Divine Farmer, is a legendary figure in Chinese mythology and is one of the ancient Chinese cultural heroes. He is credited with the invention of agriculture and traditional Chinese medicine. According to legend, Shennong tasted various herbs to determine their medicinal properties, thereby identifying poisonous plants and herbs that could be used for healing. Legend also says Shennong discovered tea when leaves from a wild tea tree blew into his pot of boiling water. This tale highlights his contribution to the development of herbal medicine in ancient China. The student draws the main character Shennong and the caption says “I can help the people in my tribe!” (Figure 3).

Figure 3 Another student’s drawing of an ER book Shennong Tasting a Hundred Herbs.

Note. The description of the drawing in English: The leader found a leaf that could help him. When he had a stomachache, eating this medicine made him feel better.

Another engaging activity is My Story. Students were encouraged to write their own stories, bring them to class, and share them with their peers. Those stories can also be used as reading materials for future students. The following story (see Table 5) written by a student talks about his experience driving bicycles in Shanghai.

Although one of the top ten ER principles is reading for its own sake (Day & Bamford, Reference Day and Bamford2002), previous research has demonstrated the benefits of ER activities (e.g., Zhou & Day, Reference Zhou and Day2021). In Zhou and Day (Reference Zhou and Day2023), 70 percent of the participants stated that they enjoyed ER activities. Five reasons contributed to their enjoyment, including providing activities to interact with classmates, solidifying comprehension, a variety of activities, different from normal classroom activities, and forcing them to read. For example, one student claimed:

Another student stated:

It is understandable that some students did not like ER activities. One of the reasons mentioned was the sharing in the class was rushed, which is understandable because they only had ten to fifteen minutes to share as a group. Another reason mentioned was it was not possible for students to know how to pronounce unknown characters without looking up the pronunciation. Since Chinese characters only include partial information about their pronunciations (through phonetic radicals), learners need to look up the dictionary if they really want to know how to pronounce a certain character. Thus, for a logographic language like Chinese, listening while reading may be worth trying.

To gather more feedback from students, teachers can ask students to write a reflection at the semester’s end. In the Chinese ER program, I prompted students to reflect by answering six specific questions. This method enables teachers to collect students’ feedback and subsequently enhance the program. Figure 4 showcases a reflection from a student in my Intermediate Chinese class.

Figure 4 End-of-the-semester ER reflection.

Though there are not too many published studies on ER in L2 Chinese context, it does not mean that enthusiastic language teachers are not implementing one or another form of ER in their teaching. Reading materials or websites have also been published or developed by publishers or language practitioners. The following is a list of online ER reading resources for L2 Chinese learners.

• The Chairman’s Bao (https://www.thechairmansbao.com)

• Ponddy Reader (https://ponddy-reader.netlify.app) (see Zhou & Zhao, Reference Zhou and Zhao2023 for the website review)

• Dada Chinese (https://dd-la.com/)

• Du Chinese (https://www.duchinese.net/lessons)

• HSK Reading (https://hskreading.com/)

• IChineseER (https://lchineseer.sites.pomona.edu)

• Mandarin Bean (https://mandarinbean.com)

Mandarin Companion published graded readers in three levels: breakthrough (150 Chinese characters), Level 1 (300 Chinese characters), and Level 2 (450 Chinese characters). Publishers in the mainland of China have also published many graded readers for learners of Chinese as well as for native Chinese-speaking children (Table 6).

4.3 Spanish

A few ER studies in learning Spanish as a foreign or second language contexts have been conducted (e.g., Hardy, Reference Hardy2013, Reference Hardy2016; Liburd & Rodrigo, Reference Liburd and Rodrigo2012). For example, Hardy (Reference Hardy2016) documented the effects of a short-term extensive reading program on Spanish proficiency, motivation to read, and attitudes toward reading in Spanish in a mixed-ability class. The study was conducted in a small, private, liberal arts college in the United States. ER was offered as a stand-alone elective course in which students at the intermediate through low-advanced levels were encouraged to enroll. The course met three hours per week for seven weeks. Most of the class time was devoted to students’ silent sustained reading. The reading materials were graded readers, adapted classics, and children and young adult books in Spanish collected by the researcher’s department. Students were also able to check out children’s, young adult, and adult literature books from a local public library. Data were collected through cloze tests, a Spanish language proficiency test (i.e., Brigham Young University’s Computer Adaptive Placement Test), a questionnaire, and reflection journals. Students also kept a reading log to record the date, the title of the book, the number of pages read, the number of minutes read, and an indication of the difficulty level of the book. The results of a cloze test showed a significant improvement in Spanish proficiency after seven weeks of ER. The reflective journals showed that ER offered opportunities for them to guess the meaning of unknown words using contextual clues. Students also found out that reading in Spanish became easier and more enjoyable. Most students identified improvements in their reading comprehension in Spanish, and many identified improvements in their vocabulary, reading fluency, and even writing and speaking abilities in Spanish. For example, the following are some quotes from students’ reflection journals (p. 58):

The study provided insightful implications for incorporating ER into L2 Spanish curriculum. The study underscored the importance of having an ample selection of books that are interesting and easy. When graded readers are unavailable, instructors can turn to children’s or young adult’s literature in a local public library, as Hardy did. Instructors’ guidance toward selecting appropriate book levels was also needed on the students’ side. Hardy (Reference Hardy2016) called for the inclusion of ER in the Spanish as a foreign language curriculum.

Liburd and Rodrigo (Reference Liburd and Rodrigo2012) investigated the effects of a five-week short-term ER program on reading attitudes and confidence of L2 Spanish learners enrolled in a second-semester Spanish class at a university in the Southeastern United States. Around 100 graded Spanish readers and 48 books at pre-Level 1 were available. At the end of the five weeks, each participant in the ER group (n = 3) read a total of 5 books for an average of 169 pages each. Among the fifteen books students selected to read, eleven were from Level 1, two from pre-Level 1, and two from Level 2. Both the ER group and the traditional group reported identical L1 reading attitude and pre-L2 reading attitude. However, the post-L2 reading attitude of the ER group improved by 1.33 while that of the control group showed no change in their attitude scores. ER also played a role in boosting confidence in the reading ability of the experimental group. The students in the ER group also supported the inclusion of ER into the Spanish curriculum. Liburd and Rodrigo’s (Reference Liburd and Rodrigo2012) study demonstrated the feasibility of incorporating ER as a supplement to L2 Spanish courses. They stated that reading a book per week is a manageable task that can be done along with the regular course curriculum. Particularly, it showed how ER could be incorporated into a lower-level L2 Spanish course as a supplement component. The results of the study, however, need to be interpreted with caution due to the very small sample size in both the control and experimental groups.

4.4 German

Same as L2 Spanish, there are only a few published studies that reported the incorporation of ER into German language programs (e.g., Arnold, Reference Arnold2009; Rankin, Reference Rankin2005). The two studies reported the implementation of ER among intermediate-level learners (Rankin, Reference Rankin2005) and advanced-level learners (Arnold, Reference Arnold2009), thus providing implications for doing ER with learners of different proficiency levels.

Rankin (Reference Rankin2005) reported on the incorporation of ER into an intermediate German course at Princeton University. The course where ER was incorporated was German 102-5, an honors section of Intermediate German. Students were highly motivated and had higher expectations for the course. The reading materials for the course were a combination of short stories and internet texts. After consultation with students and taking other factors into consideration, it was decided that ER would be done after class, for a minimum of one to two hours per week. There was also no requirement on the number of books read, rather, it would be the time involved that counted. Students were asked to turn in book reports, briefly explaining the texts read and providing an evaluation. The reading materials used included the Easy Reader series from Klett Verlag and texts in Langenscheidt’s series of Leichte Lekütren (p. 128). Readers can refer to Rankin (Appendix A) for a list of graded readers in L2 German. Data were collected using reading report sheets, an anonymous survey at the end of the semester, and a formal interview with some students. The researcher was interested in students’ perceptions of ER materials. Students reported that ER materials gave them a sense of empowerment and enjoyment in the act of L2 reading. For example, here is one quote from one student:

Some respondents responded that ER helped with their German grammar, a greater comprehension of the German language, and lexis. What also appealed to the participants was that ER allowed them to read at their own pace and there were no tests. However, at the same time, students suggested that ER could be more structured (e.g., add vocabulary quizzes, more frequent book reports, and write book journals) and assign a reading amount each week (e.g., one book a week). Rankin (Reference Rankin2005) concluded that ER, if properly organized, can succeed in creating a positive attitude in learners toward the learning of German that transcends “a grade-mongering” and “a learn-for-the-test” mentality (p. 131).

Arnold (Reference Arnold2009) evaluated the effects of ER among a group of advanced learners of German as a foreign language. ER was implemented in an advanced composition and conversation class. Each class lasted seventy-five minutes and students met twice per week. Over the course of the semester, seven ER sessions were conducted in computer labs. The instructor introduced a list of German websites (i.e., newspapers, magazines, news and radio stations, blogs, and others) to the students (see p. 364 Appendix A in Arnold, Reference Arnold2009). Students were encouraged to read what interested them without using a dictionary. Students read for the majority of the time in seventy-five minutes each class and then were asked to fill in a reading report before engaging in a follow-up reading discussion. The reading reports were part of a reading portfolio which was worth 30 percent of students’ final grade. The reading reports were graded using a rubric that evaluated whether students analyzed the reading materials in terms of their content, genre, formality level, purpose, reflected on their reading processes, documented their reading strategies, and so on. The reading reports and questionnaire data showed that students read authentic texts on a wide range of topics that matched their interests. Almost 62 percent of students reported that they enjoyed reading the online materials in ER sessions. Students also used dictionaries, but mainly after reading. They realized the disruptive nature of dictionary use and were more comfortable reading without knowing each word. All students reported being more confident in their ability to read German and felt that they had become better readers in German. Overall, students were enthusiastic about selecting reading materials by themselves. One student (Laura) commented, “half the fun is in choosing” (p. 358). This accorded with Principle #3 Learners choose what they want to read of the top ten ER principles of Day and Bamford (Reference Day and Bamford2002). It seemed that students were able to select reading materials they felt comfortable reading and understand on average 84 percent of what they read. An interesting finding from Arnold (Reference Arnold2009) was that five out of eight participants purposely chose more difficult texts to challenge themselves. This accorded with advanced learners in Tabata-Sandom (Reference Tabata-Sandom2023) where they gained a sense of achievement from reading challenging high-level readers on Xreading.com. As Arnold stated, those advanced learners made “conscious decisions” about a text’s difficulty level and challenged themselves on purpose (p. 359). Arnold’s approach was particularly valuable for upper-division language courses with students of heterogeneous proficiency levels and diverse needs.

4.5 Japanese

A few ER studies have been conducted in Japanese as a foreign language (JFL) or Japanese as a second language (JSL) context (e.g., Hitosugi & Day, Reference Hitosugi and Day2004; Leung, Reference Leung2002; Suzuki & Kumada, Reference Suzuki and Kumada2018; Tabata-Sandom et al., Reference Tabata-Sandom, Banno and Watanabe2023).

Leung (Reference Leung2002) examined the impact of ER on Wendy’s (pseudo name) self-study of Japanese over a twenty-week period. Wendy lived in Hongkong for twenty years. Chinese was her first language and English was her second language. She was pursuing her master’s degree in ESL (now Second Language Studies) at the University of Hawai’i at Manoa. The study was conducted in two stages, covering nine and eleven weeks respectively. By the end of the study, Wendy read thiry-two books, mainly comic books and children’s books. Wendy kept diaries, recording her experience and the progress of reading Japanese. Occasionally, she also talked to her EFL professor about her progress and concerns about her learning Japanese through emails or after-class discussions. In the second stage, Wendy was also able to find a Japanese friend who helped her with her Japanese study for half an hour to one hour each week. Results of a modified Paribakht and Wesche’s vocabulary test showed that Wendy’s vocabulary knowledge increased by 23.5 percent in one month. The journal entries showed that ER reinforced her existing knowledge of certain vocabulary items and allowed her to apply her vocabulary knowledge in a meaningful way. Since Wendy was reading children’s and comic books, she also learned some expressions that would not be normally found in textbooks. Wendy was also able to guess the meanings of unknown words and learned words incidentally. The following journal entry showed how she figured out the meaning of a word through multiple encounters in different contexts (Leung, Reference Leung2002, p. 73, Journal entry, Week 16).

Wendy also improved her reading comprehension of Japanese. She had a hard time decoding hiragana at the beginning, At the end of the study, she was able to understand simple Japanese children’s stories. Wendy’s attitude to reading also fluctuated. In the beginning, she was excited, then she was frustrated because she could not find reading materials appropriate for her level. As her reading proficiency improved, she became more confident. She was also more tolerant of the complexity of the language and more motivated to improve her reading proficiency.

As could be expected, Wendy encountered some challenges in her self-ER reading, such as the difficulty of finding appropriate reading materials and time to read. Wendy, nevertheless, actively overcame those issues. She not only checked out books from a local library, but also turned to Japanese friends for advice, especially those with young children in the family. The implication of Wendy’s experience is that if appropriate reading materials are available, it is possible that a beginning foreign language learner can practice ER and can “reap the benefits” (p. 79).

Hitosugi and Day (Reference Hitosugi and Day2004) elaborately reported the establishment of an ER program in a JFL context, the requirements of the program, the assessment of the reading, and students’ perceptions. An ER component was incorporated into Jpn 102, a first-year, second-semester Japanese course at the University of Hawai’i at Manoa. Hitosugi and Day (Reference Hitosugi and Day2004, p. 23) stated that in order to add ER to Jpn 102, they need to address six key issues:

1. 1. What would the students read?

2. 2. Would the reading be required, with credit awarded, or would students simply be encouraged to read on an optional basis for the benefits it would have on their language learning?

3. 3. How much reading would the students be required to do?

4. 4. Would ER be done for homework, in class, or both?

5. 5. How could we incorporate the students’ reading into the course?

6. 6. How could we measure the impact, if any, of reading extensively on the students’ learning of Japanese?

Those key issues revolved around different aspects of ER as a teaching approach, including materials, the role of ER in the curriculum, reading amount, the format of ER, and assessment.

As for the reading materials, they collected 266 used and new books and classified them into 6 levels based on Hitosugi (Reference Hitosugi2000) and with reference to proficiency levels of ACTFL. The number of books for each level was Level 1 (39), Level 2 (76), Level 3 (50), Level 4 (87), Level 5 (11), and Level 6 (3). The researchers also color-coded the levels so that students could easily select books. They assigned 10 percent of the final course grade to ER, thus making ER a required part of the course. This is different from some studies (e.g., Liburd & Rodrigo, Reference Liburd and Rodrigo2012) where ER was a voluntary task.

As for the reading amount or reading target, as Hitosugi and Day named it (p. 26), students were required to read forty books over a ten-week period, which means four books a week. If students read over forty books, a 5 percent bonus credit would be awarded for reading an additional twenty books. Different from Zhou and Day (Reference Zhou and Day2023) where students read Chinese books both in and outside of the class, Hitosugi and Day decided to assign ER as part of homework to make sure that students keep up with those in the other eleven Jpn sections, which is also a practical issue to consider when one course has multiple sections. However, every week approximately thirty minutes of the class time were allocated to ER activities. For example, students may be asked to promote their favorite books, act out the story, or create sentences using vocabulary from the story. According to Hitosugi and Day (Reference Hitosugi and Day2004), classroom activities “validated” their ER (p. 27), strengthened the class as a “language-learning community” (p. 27), and served as an incentive for the students to do reading after class. I feel that Hitosugi and Day (Reference Hitosugi and Day2004) provided very clear and step-by-step guidance of how to establish an ER program in L2 Japanese contexts. Also conducted at the University of Hawai’i at Manoa, Mohar’s study (Reference Mohar2024) examined the implementation of ER among beginning Japanese learners in a university in the USA, the study revealed that beginning Japanese learners prefer graded readers over children’s books and physical books over online materials, which provided pedagogical implications for material selection among beginning-level L2 Japanese readers.

While Hitosugi and Day’s study was conducted in a JFL context, Tabata-Sandom et al. (Reference Tabata-Sandom, Banno and Watanabe2023) carried out a study on extensive reading (ER) in L2 Japanese within Japan. Their study involved eleven upper-intermediate to advanced-level undergraduate and graduate students studying Japanese at a national university in western Japan, who were enrolled in an elective ER course titled “Learning Japanese through ER.” This course spanned two consecutive semesters, totaling sixteen weeks. The reading materials included 130 Japanese graded readers, comic books, books intended for native children, and books targeting native readers. Students were encouraged to engage in reading both in and outside the classroom, with those reading forty books achieving full marks. On average, each participant read 36.7 books per term. Echoing the findings of Hitosugi and Day (Reference Hitosugi and Day2004), this study also noted individual differences in the number of books read, with the most avid readers completing 140 books over the two terms and the least active reader finishing only 44 books. Unlike other ER studies in the L2 Japanese context, Tabata-Sandom et al. (Reference Tabata-Sandom, Banno and Watanabe2023) explored the impact of ten speed reading training sessions on the participants’ reading rate. The results indicated a significant increase in reading speed across three different measurement methods, without compromising comprehension. Consequently, Tabata-Sandom et al. (Reference Tabata-Sandom, Banno and Watanabe2023) advocated for the integration of a speed-reading component into ER programs.

4.6 French

There are not many published studies on ER in French as a foreign or second language. Besides Pigada and Schmitt (Reference Pigada and Schmitt2006), which examined the learning of French words through extensive reading (please see 3.2 Vocabulary), I was able to find one master’s thesis written in French. Jourdan-Ôtsuka (Reference Jourdan-Ôtsuka2022) conducted an ER study at the Kyoto University of Foreign Studies to examine the effectiveness of ER (LEx, which stands for Lecture Extensive) in French as a foreign language among 100 native Japanese students. This research, situated within the French Studies Department, primarily involved students who began their French language learning journey at the university. Most had only previously studied English in their primary and secondary education. The objective of the students was to elevate their French proficiency from A2 to B1 level within a four-year timeframe.

The study used a diverse range of materials, primarily short and highly illustrated books, including children’s picture books and online resources. These books were strategically chosen and classified based on word count to align with the students’ varying proficiency levels. The 100 participants on average read 17 books. Participation in the LEx program was incorporated as a part of the curriculum, substituting a written comprehension exam and contributing to 25% of the final grade. Remarkably, 96% of the participants met the reading targets set by the program. To gauge the students’ language proficiency and motivation, the Test de Connaissance du Français (TCF) online and end-of-semester surveys were utilized. The surveys also provided insights into the students’ perceptions of the LEx program and their general reading habits.

The study revealed that L1 Japanese students learning French as a foreign language reported an increased interest in reading and a deeper appreciation of Francophone cultures. The study also revealed that learners in the more organized programs tended to perform better in the number of books read, average length of the books read, and total number of words read.

4.7 Italian

Adopting a longitudinal pre-post design, Aliyar and Peters (Reference Aliyar and Peters2022) investigated the effects of reading comic books on incidental vocabulary learning in an L2 Italian context. The participants were thirty-five Iranian learners of Italian as a foreign language with a mean age of 20.5 years old. Around 25 of the participants in the experimental group read and then read while listening to four comic books in a four-week period. The four comic books used in the study were Una Storia Italiana, Il Mistero di Casanova, Rigoletto, and Habemus Papam. Three aspects of vocabulary knowledge (i.e., form recall, meaning recall, and form recognition) of eighty-two Italian words that appeared in the comic books were selected as target words. Concerning the form recall format, students were asked to translate Persian words into Italian words. As for the meaning recall, the participants were asked to translate Italian target words to Persian. For the form recall test, the authors asked the participants to indicate the level of familiarity with each target word by choosing between three options (1. I have never seen this word before; 2. I have seen this word, but I don’t know its meaning; 3. I know the meaning of this word.). The results showed that vocabulary could be learned incidentally through reading and reading while listening without explicit instruction. The qualitative data showed that most students loved learning Italian by reading comic books because the experience was pleasurable. They also stated that they would continue reading comic books in the future. Aliyar and Peters (Reference Aliyar and Peters2022) suggested that comics are a valuable and effective source of learning Italian, and their inclusion in L2 Italian teaching and learning can be particularly advantageous to L2 learners, especially those with elementary Italian proficiency.

5.1 Rural Settings

Language educators might be extremely interested in implementing ER in rural schools where reading might be the only language input for learners. Mohd Asraf and Ahmad (Reference Mohd Asraf and Ahmad2003) introduced their experience of implementing an ER program, which they called the Guided Extensive Reading program, among a group of Malaysian rural school students. The students were from the 7th and 9th grades at three schools. The majority of the students from the three schools hardly speak English at home or school. Some of them spoke Malay at home, while some students spoke a Chinese dialect at home. The parents of the majority of the students were farmers or factory workers. Since the students had a very limited vocabulary in English, they read books at several levels below their actual grade level. One day of a week was assigned to ER where students read silently and then retell what they have read to their classmates. Teachers helped the students with difficult vocabulary. Data were collected through classroom observations, in-depth interviews with both teachers and students, and teacher diaries. Initial observation showed students did not read English books regularly and did not enjoy reading in English. As a result, they had difficulty understanding the stories they read and looked up the meanings of words in dictionaries often although they were advised not to do so. Students also had difficulty retelling the stories in the first ER sessions. As a result, some of them merely copied texts from the stories and read them out. As the semester progressed, students were more motivated to read in English, felt that ER was beneficial to them, and grew to like reading English books. As Mohd Asraf and Ahmad (Reference Mohd Asraf and Ahmad2003) concluded, students in rural schools could and did benefit from ER. The majority of the students developed positive attitudes toward reading in English. Further research is needed on ER in rural settings, where there may be a scarcity of reading materials and students might possess lower language proficiency levels compared to their peers in urban schools.

5.2 Advanced Learners

Advanced learners are, according to Tabata-Sandom (Reference Tabata-Sandom2023), “an under-researched population” in ER (p.160). In the ER field, learners are categorized as advanced either by their vocabulary size (i.e., Tabata-Sandom, Reference Tabata-Sandom2023), by the level of courses being taken (e.g., an advanced composition and conversation class in Arnold, Reference Arnold2009), or by the results of certain types of proficiency tests (e.g., EAP students who took an English proficiency test in Zhou & Day, Reference Zhou and Day2021).

Tabata-Sandom (Reference Tabata-Sandom2023) labeled the participants as advanced learners based on the average of their vocabulary sizes of 7,081 word families. The eleven participants aged between thirty and sixty-five whose L1 was Japanese were recruited via Facebook groups and a local book club and read graded readers on an online reading website for one year. On average, the 11 participants read 1,146,821 words over a year. The researcher found that many participants in her study completely embraced graded readers due to their comprehensibility. Through reading a large number of materials, the participants’ vocabulary size increased significantly, with a medium effect size of d = 1.04. The participants’ reading rate also increased from 123.8 SWPM to 153.2 SWPM. Overall, the study revealed that advanced L2 readers transformed from unconfident readers to engaged and avid L2 readers. Tabata-Sandom (Reference Tabata-Sandom2023) identified comprehensible and intriguing reading materials, soft enforcement (a sense of commitment to the ER project and consistent support from the researcher), high L2 reading abilities, and positive reading attitudes as the sources behind the change. Tabata-Sandom (Reference Tabata-Sandom2023) demonstrated how to start an ER program among mature adult learners with high L2 proficiency levels who are no longer enrolled in any language courses. Tabata-Sandom’s (Reference Tabata-Sandom2023) study shed light on the role played by ER in L2 language geragogy (i.e., the education of older individuals).

Instead of using graded readers as in Tabata-Sandom (Reference Tabata-Sandom2023), another ER study with advanced learners introduced a list of German websites (i.e., newspapers, magazines, news and radio stations, blogs, and others) to the students in a German as a Foreign Language context (Arnold, Reference Arnold2009). Students appreciated the learner autonomy in material selection and held positive views of ER.

The implementation of ER with advanced language learners may encompass several key considerations: Firstly, it is essential to take the learners’ proficiency levels into account during the preparation of materials and design of activities. Secondly, granting learners autonomy in the selection of reading materials, in particular challenging but intriguing materials, can be highly beneficial. Despite their higher language proficiency, advanced learners may experience reluctance or anxiety while reading in a foreign language, as noted in Tabata-Sandom’s (Reference Tabata-Sandom2023) study. Therefore, it is both advisable and beneficial to encourage advanced learners to read extensively.

5.3 EAP Contexts

Fifteen years ago, Macalister (Reference Macalister2008) claimed that ER appeared to be particularly absent in higher educational and EAP settings. Fifteen years later, it would be safe to say that ER has gained popularity in universities, but I am afraid what Macalister said about ER in EAP settings still holds true today. There are only a few ER studies conducted in EAP contexts (e.g., Kim & Ro, Reference Kim and Ro2023; Macalister, Reference Macalister2008; Park, Reference Park2016; Ro, Reference Ro2018). However, ER can be a valuable teaching and learning approach in EAP contexts.

Macalister (Reference Macalister2008) incorporated ER in a twelve-week university preparation EAP course in New Zealand. The course was designed to prepare students for university study. Students read silently for twenty minutes (sustained silent reading) at the end of each morning, with the teacher also “modelling good reading behavior” by reading silently with students (p. 250). Students were encouraged to read on their own time and as much as possible but were required to read at least two graded readers per week. The reading materials could be borrowed from the university’s language learning center. Overall, the inclusion of ER as a component in the EAP course was positively perceived by the learners and to some extent created positive attitudes toward reading. Macalister (Reference Macalister2008) was confident that ER can definitely “have a place” in EAP classrooms (p. 255).

Integrating reading and writing through ER, as Park (Reference Park2016) argued, could be a valuable approach to help EAP learners deal more easily with the enormous amount of reading and writing in academic settings. University students expressed negative attitudes such as fear, anxiety, and stress toward academic reading in English (Eriksson, Reference Eriksson2023) and integrating reading and writing is a challenge faced by EAP students (Grabe & Zhang, Reference Grabe and Zhang2013). Comprehensible input provided by ER may have led to a pleasurable and less demanding writing experience, which in turn may have enhanced learners’ writing fluency and facilitated L2 writing development.

Park (Reference Park2016) explored the role of ER in L2 writing ability in an EAP program. Fifty-six participants were from two writing classes, a traditional one and an ER-oriented one. Students in the ER-oriented writing class spent fifteen minutes reading graded readers and five minutes discussing their reading in pairs or groups, while students in the traditional writing class spent fifteen minutes on free writing, followed by five minutes of pair discussion. ER group borrowed books from the ER library which contained around 250 books of both fiction and nonfiction (e.g., biography and history). The graded readers were mainly from Oxford Bookworms by Oxford University Press and Cambridge English Readers by Cambridge University Press. Both classes were also required to spend around one and a half hours on homework per week. While the traditional writing class participants were given textbook-based homework each week (e.g., writing short essays, grammar exercises), the ER-oriented class participants were asked to continue ER and complete a writing activity based on the books they read to practice writing skills such as summarizing, describing, analyzing, creative writing and so on. To measure the writing ability, essay tests with the prompt “What is your attitude towards writing?” were administered at the beginning and the end of the semester. The results showed that the ER class outperformed the traditional class in five sub-skills of writing: content, organization, vocabulary, language use, and mechanics. It seemed that ER helped students learn how to use words and expressions in appropriate contexts and produced more natural-sounding sentences (Park, Reference Park2016).

Through continuous encounters with grammatical expressions, students may have learned new grammar knowledge or strengthened their existing knowledge of English grammar, such as subject–verb agreement, singular/plural nouns, prepositions, articles, and so on (Park, Reference Park2016). Similarly, Kim and Ro (Reference Kim and Ro2023) also showed that an ER group significantly improved in the length of sentences, the number of clauses, and the number of verb phrases compared to students in a control group. ER group also used frequent verbs and verb construction combinations to a lesser extent.

Zhou and Day (Reference Zhou and Day2021) investigated whether reading self-selected easy books could improve academic reading and different aspects of language abilities in EAP settings. Fifty-seven undergraduate and graduate EAP learners participated in the ER program. The students were from two EAP courses: intermediate and advanced academic reading courses. Both EAP reading courses met for seventy-five minutes, twice a week, for sixteen weeks. Online ER was required and implemented in both courses. The number of words required to read differed in two instruction levels: 10,000 words per week for the intermediate EAP reading course and 13,000 for the advanced EAP reading course in the Fall 2017 semester (reduced to 12,000 for the Spring 2018 semester). Students were asked to read online from Xreading.com each week and take online quizzes with 60% accuracy. Around 10% of the course grade was assigned to ER in both courses. The study collected both quantitative data (i.e., pre- and post-reading attitude questionnaires, students’ online reading records), and instructors’ and students’ interviews. Overall, 57 EAP learners spent 14 hours reading extensively online and read 18 books and 91,077 words in one semester. As for whether ER improved their academic reading, 45 percent of the interviewees agreed that ER improved their academic reading ability. The interview data showed that ER made them feel confident and comfortable in reading, which further motivated students to read academic materials like textbooks.

Besides having a direct impact on EAP reading ability, ER may also indirectly influence EAP reading ability through the mediation of affective factors such as confidence or comfort. This is especially important in EAP contexts because academic reading tasks such as reading research articles and textbooks, summarizing, and writing literature reviews, and so on are often daunting tasks. Gaining confidence and feeling comfort in reading graded materials may make EAP students get used to reading. Confidence in one’s reading ability is an important affective variable in creating independent readers (Liburd & Rodrigo, Reference Liburd and Rodrigo2012). Excerpt 1 from Zhou and Day (Reference Zhou and Day2021) demonstrated how ER impacted academic reading ability. Excerpt 2 is a suggestion from one interviewee.

Excerpt 1

There is no denying that graded readers and research articles or textbooks differ in many ways. Some interviewees did not agree that ER contributed to their academic reading ability. Two reasons EAP students mentioned included: (1) reading materials are not on academic topics and (2) students did not select to read academic books (Zhou & Day, Reference Zhou and Day2021). One interviewee said that ER and academic reading are not related. One instructor also mentioned that there were complaints from students that many books on Xreading are for children and “childish.” One suggestion, as stated in Excerpt 3, might be that teachers play a bigger role in material preparation. This accords with one suggestion in Teng’s (Reference Teng2023) discussion piece of Zhou and Day (Reference Zhou and Day2021).

Excerpt 2

Teachers can enrich the ER experience in EAP contexts by diversifying the reading materials. This can include newspapers, magazines, online resources (e.g, Arnold, Reference Arnold2009), and academic texts. It is important to tailor these materials to EAP learners’ individual interests, their proficiency levels, and their specific academic objectives. Additionally, language instructors should offer ongoing guidance and support to EAP learners. Providing personalized scaffolding is crucial for the effective implementation of ER in EAP settings.

5.4 Online ER

With the development of technology over the recent decades, using online information to read is an integral part of our lives. Reading has transformed from printed papers to a variety of digital texts. The new trend has dramatically changed the direction of ER and offered opportunities for language teachers to incorporate online ER into their course syllabus (Bui & Macalister, Reference Bui and Macalister2021). The advantages of ebooks over physical books have also been supported in previous research (e.g., Cote & Milliner, Reference Cote and Milliner2015; Jeon & Day, Reference Jeon and Day2016). Recent five years have witnessed many online ER studies (e.g., Bui & Macalister, Reference Bui and Macalister2021; Perez, Reference Perez2022; Puripunyavanich, Reference Puripunyavanich2022; Rezaee et al., Reference Rezaee, Farahian and Mansooji2021; Tabata-Sandom, Reference Tabata-Sandom2023; Zhou & Day, Reference Zhou and Day2021). Online ER studies refer to studies that use online reading materials, such as graded readers, newspapers, magazines, video clips, and so on.

Puripunyavanich (Reference Puripunyavanich2022) implemented an online ER program among 5,000 freshmen at a university in Thailand. An online ER reading platform, Xreading.com, was used because it suited the large-scale implementation of ER in that university with ease of access, the ability to track and monitor the reading progress, and a variety of reading materials at different levels (Puripunyavanich, Reference Puripunyavanich2022). The study attributed the success of the ER program to five factors, including the integration of ER into the curriculum, the availability of reading materials, the institution’s support, teachers’ roles, and the use of an online platform. Zhou and Day (Reference Zhou and Day2021) and Tabata-Sandom (Reference Tabata-Sandom2023) also adopted Xreading.com because it enabled learners and researchers in both studies to monitor individual reading progress closely. Rezaee et al (Reference Rezaee, Farahian and Mansooji2021) showed that some Iranian EFL learners preferred working with multimedia texts (e.g., video clips, audio files, pictures, hyperlinks) over physical books. Cost is another factor influencing the choice of e-materials over physical books (e.g., Cote & Milliner, Reference Cote and Milliner2015; Puripunyavanich, Reference Puripunyavanich2022). Electronic materials can be offered at lower costs compared to physical books (Cote & Milliner, Reference Cote and Milliner2015).

Some instructors also developed their own online ER platforms to meet specific reading needs of their students. For example, Bui and Macalister (Reference Bui and Macalister2021) developed a reading website called Extensive Reading Online (ERO) on wordpress.com for seventeen EFL learners at a university in Vietnam. The reading materials in this small-scale digital library were adapted and collected from a number of online resources such as English ER Central, gradedreading.com, Lit2Go, Paul Nation’s website, World Stories UK, and 365 ESL short stories (p. 6). In order to provide the most natural reading experience, the website only integrated two functions: a stopwatch to enable students to record their reading time and an online progress graph for them to keep track of their reading progress.

With the help of my institution’s IT department, I developed an online ER website IChineseER (https://lchineseer.sites.pomona.edu) for L2 Chinese learners. The website provides over 300 graded reading materials on topics related to Chinese culture such as holidays, Chinese food, ethnic groups, idioms, and jokes. The materials were categorized into 6 levels (A1 = 4; A2 = 84; B1 = 52; B2 = 83; C1 = 53; C2 = 5) with reference to the Common European Framework of Reference for Languages (CEFR).

L1 Japanese EFL learners in Li et al. (Reference Li, Majumdar, Chen, Yang and Ogata2023) read on BookRoll ebook reader, a teaching resource distribution system designed to access ebooks and lecture slides. BookRoll ebook reader provided 400 ebooks. Students can navigate the reading content page by page, make markers in yellow or red, create memos, or search keywords in an ebook. More importantly, students’ reading behaviors can be recorded and stored for research or teaching purposes. Thus, with some help from IT experts, language teachers can establish online reading platforms that cater to learners’ needs in specific contexts.

In conclusion, the evolution of technology and the transition to digital media have significantly influenced the implementation of ER. Online ER platforms not only facilitate the tracking and monitoring of reading progress but also integrate multimedia elements to enrich the learning experience, underscoring the significant opportunities that online ER brings to the teaching and learning of reading.

6.1 Challenges

Despite the beneficial merits of ER, it is still a less commonly adopted approach to language teaching (e.g., Chang & Renandya, Reference Chang and Renandya2017; Ewert, Reference Ewert, Dressman and Saddler2020; Renandya & Jacobs, Reference Renandya, Jacobs, Richards and Renandya2002; Robb & Ewert, Reference Robb and Ewert2024) and the ER approach “has not become more popular” (Robb, Reference Robb2022, p. 184). As Jeon and Day (Reference Jeon and Day2016) observed, ER is yet not widely practiced in language classrooms, particularly in EFL settings (Jeon & Day, Reference Jeon and Day2016). Bui and Macalister (Reference Bui and Macalister2021) stated that the implementation of ER seems to be limited in many higher education classrooms due to teachers’ time commitment (Grabe, Reference Grabe, Belcher and Hirvela2001) and the skeptical view of language educators. Alahirsh (Reference Alahirsh2014) identified the main obstacles to implementing an ER program as limited time allocated for reading, the cost associated with purchasing reading materials, and challenges in managing a program. A peruse of the literature (Chang & Renandya, 2017; Grabe, Reference Grabe2011; Haider, Reference Haider2012; Huang, Reference Huang2015; Macalister, Reference Macalister2010; Renandya & Jacobs, Reference Renandya, Jacobs, Richards and Renandya2002; Renandya et al., 2020; Renandya et al., Reference Renandya, Ivone and Hidayati2021; Robb, Reference Robb2022) reveals a list of challenges pertaining to students, teachers, curriculum, materials, and so on.

6.2 Strategies