Recently there has been some debate about the appropriacy of different lexical units in pedagogy and research (e.g., Brown et al., 2020; Dang & Webb, 2016a; Kremmel, 2016; Laufer & Cobb, 2020; McLean, 2018; Nation, 2016; Nation & Webb, 2011; Vilkaitė-Lozdienė & Schmitt, 2020). The lexical unit (word types, lemmas, flemmas, word families) needs to be considered when developing wordlists, vocabulary tests, and vocabulary learning programs. It is also central to the lexical profiles of text and corpora, which indicate the vocabulary learning targets associated with understanding different types of discourse. Perhaps most importantly, the lexical unit of words found in vocabulary learning resources such as word lists and tests may affect their pedagogical value. The aim of this article is to highlight aspects of research and pedagogy that are affected by lexical units and describe issues that should be considered when operationalizing words in studies of vocabulary and learning resources.

There has been limited research on the efficacy of captioned second language (L2) television in facilitating the incidental acquisition of multiword expressions (MWEs). The present study aims to fill this gap. Additionally, this study examines the role of typographic enhancement and repetition. One-hundred and twenty-two L2 learners were assigned to one of six conditions that differed in terms of caption condition (no captions, normal captions, enhanced captions) and the number of times they watched the same video (once, twice). The participants took a cued MWE form recall test before watching the video, immediately and 2 weeks after watching it. A content comprehension test was also administered. Compared to single viewing, repetition resulted in better content comprehension as well as better acquisition of MWEs. Both caption types positively influenced MWE recall relative to watching the video without captions, but typographic enhancement reduced the benefits of captions for content comprehension.

This study combines explicit (pen-and-paper) and sensitive (time-pressured) measures to gauge the impact of three instructional interventions (contextualized input with meaning-focused activities, contextualized input with word-focused activities, and decontextualized input with word-focused exercises) on the learning of 20 L2 French target verbs. Participants (N = 313, L1 = Dutch) completed a combination of explicit (form recognition, meaning recall, grammatical preference) and time-pressured sensitive tests (lexical decision, semantic relatedness, grammaticality judgment) as immediate and delayed posttests. Explicit posttests show the beneficial effects of word-focused instruction, and underline the efficiency of context for meaning-related knowledge. Sensitive posttests generally confirm the explicit results, but reveal differences between both word-focused conditions related to lexical processing and strength of knowledge. This study suggests that combining explicit and sensitive measures can provide a more complete picture about the effects of L2 vocabulary instruction and shows that contextualized and decontextualized word-focused instruction benefit vocabulary learning in a complementary way.

Although retrieval of lexical forms is a prerequisite for language production, research of L2 vocabulary learning has focused much more on meanings and form-meaning mappings than on development of detailed, accessible mental representations of forms. This is particularly true with respect to multi-word items (MWIs). We report an experimental study involving a variety of intra-lexical, usage-based, and interlingual co-determinants of L2 vocabulary learnability pertaining to MWIs. Each learner (N = 60) encountered a randomly allocated set of 26 two-word MWIs (Nsets = 4) semi-randomly drawn from a larger pool of MWIs. Learners were asked to remember either the 13 MWIs showing the form variable assonance (e.g., change shape) or the 13 nonassonant control MWIs (e.g., sound good). Posttests of form recall revealed a large, durable effect of the focusing task in combination with forewarning of testing. Except when MWI concreteness (a semantic variable) was high, assonance had a positive effect on retrievability in recall tests given after delays of 15 minutes and one week. There was a consistent effect of the semi-semantic variable Mutual Information. Even in the context of a strong focus on forms, form variables are not the only variables that matter.

To probe the limits of attention raising through form-focused instruction, second-language research must adapt to the needs of a technologically driven learning environment. In this study, we used a randomized control design to investigate the effect of captioned media on the learning of vocabulary and grammar in L2 Spanish (n = 369 learners). Through four data-collection sessions, participants were presented with a grammar-lesson video and a multimodal video with one of three captioning formats: textually enhanced target vocabulary, textually enhanced target grammar, or no captioning. Results show strong immediate effects of captioning on target vocabulary, with additional effects of captioning on some, but not all, target-grammar structures. The findings demonstrate that (a) the learning of some grammatical structures is more conducive to captioning than others, and (b) there is space for future investigation into the factors that may influence the effectiveness of multimodal interventions, such as prior knowledge or frequency of use.

Higgins’s (2000) regulatory fit theory proposes that a fit between one’s regulatory state and strategic means for reaching a goal increases motivational strength and engagement. This study investigates how regulatory fit affects the L2 acquisition of lexical stress in an authentic learning context. Ninety EFL students were assigned to either gain frame or loss frame conditions. They engaged in speech practice in which they mimicked a model speech in English to win a chance to enter a prize raffle. The reward system was framed differently in the two framing conditions, with the intention of eliciting the participants’ use of eager or vigilant strategies, thus creating fit and nonfit conditions. Acquisition of lexical stress was assessed using pre- and posttest scores. Multiple regression analysis showed no regulatory fit effects and no loss frame effects but did show a significant beneficial effect of the gain frame on the acquisition of lexical stress.

In paired-associate learning, there are two learning directions: L2 to L1 (L2 words as stimuli and L1 words as responses) and L1 to L2 (L1 words as stimuli and L2 words as responses). Results of previous studies that compared the effects of the two learning directions are not consistent. We speculated that the cause of this inconsistency may be L2 proficiency, as the strengths of the lexical links between L2 and L1 are different depending on the learner’s L2 proficiency. This hypothesis was examined with 28 native speakers of Japanese learning English. Participants studied novel English words in the two learning directions. The results of posttests showed that for lower-proficiency learners, L2-to-L1 learning was more effective than L1-to-L2 learning, while for higher-proficiency learners, L1-to-L2 learning was more effective. The findings suggest that L2 proficiency influences the effects of learning direction on vocabulary learning.

This study is a conceptual replication of Rogers and Cheung’s (2018) investigation into distribution of practice effects on the learning of L2 vocabulary in child EFL classrooms in Hong Kong. Following a pretest, treatment, delayed posttest design, 66 primary school students (Cantonese L1) studied 20 vocabulary items over three training episodes under spaced-short (1-day interval) or spaced-long (8-day interval) learning conditions. The spacing of the vocabulary items was manipulated within-participants, and learning was assessed using crossword puzzles following a 4-week delay. While Rogers and Cheung (2018) resulted in minimal overall learning with a slight advantage for the spaced-short group, this study found large learning gains across the experimental conditions with no significant differences between the two learning schedules. Taken together, these results provide evidence that the results from previous research examining input spacing with adult populations in laboratory contexts might not generalize to authentic child learning contexts.

The present study investigated the effects of exposure to Chinese orthography on learning phonological forms of new words in learners of Chinese as a second language. A total of 30 adult learners of Chinese studied spoken label and picture associations presented either with phonologically accurate characters, characters with partial phonological information, or no orthography. Half the phonologically accurate or partially accurate characters were semantically transparent or opaque. Spoken labels were recalled without orthography presence. Results showed that exposure to phonologically accurate and semantically transparent characters during learning did not enhance the recall of the spoken labels compared to no orthography. But exposure to characters with partial phonological information and semantically opaque characters significantly hindered vocabulary learning. The implications for Chinese as a second language vocabulary acquisition and instruction are discussed.