Previous research on motion expression indicates that typological properties influence how speakers select and express information in discourse (Slobin, 2004; Talmy, 2000). The present study further addresses this question by examining the expression of caused motion by adults and children (three to ten years) in French (Verb-framed) vs. English and German (Satellite-framed). Participants narrated short animated cartoons showing an agent displacing objects and varying along several dimensions (Path, Manner). A significant increase with age was found in the number of expressed motion components in all languages, as well as an influence of Path (vertical > boundary crossing). However, at all ages, participants encoded more information in English and German than in French, where more variation and structural changes occurred with increasing age. These findings highlight both cognitive and typological factors impacting the expression of caused motion in development. Implications of our findings are sketched in the ‘Discussion’.

This longitudinal study assessed three acoustic components of maternal infant-directed speech (IDS) – pitch, affect, and vowel hyperarticulation – in relation to infants’ age and their expressive vocabulary size. These three individual components were measured in IDS addressed to infants at 7, 9, 11, 15, and 19 months (N = 18). All three components were exaggerated at all ages in mothers’ IDS compared to their adult-directed speech. Importantly, the only significant predictor of infants’ expressive vocabulary size at 15 and 19 months was vowel hyperarticulation, but only at 9 months and beyond, not at 7 months, and not pitch or affect at any age. These results set apart vowel hyperarticulation in IDS to infants as the critical IDS component for vocabulary development. Thus IDS, specifically the degree of vowel hyperarticulation therein, is a vehicle by which parents can provide the most optimal speech quality for their infants’ linguistic and communicative development.

This study investigates Mandarin-speaking children's knowledge of event semantics in interpreting spatial modifiers with zai ‘at’ after a posture verb or before a placement verb. The event-semantic principles investigated include subevent modification (Parsons, 1990) and aspect shift (Fong, 1997). We conducted an experimental study using modified forced choice, video choice, and elicited production techniques with five groups of children (two- to six-year-olds) and an adult control group. Three-year-olds were sensitive to the ambiguity of zai-PPs with placement verbs and posture verbs, suggesting guidance from principles of aspect shift and subevent modification. On the other hand, distributional properties of the input play a role in acquiring the interpretation and word order of zai: e.g., four-year-olds significantly differed from adults in accepting non-target V-zai sentences, as some verb classes can take postverbal prepositional phrases with zai while others cannot in adult usage.

Despite the body of research on auditory–visual speech perception in infants and schoolchildren, development in the early childhood period remains relatively uncharted. In this study, English-speaking children between three and four years of age were investigated for: (i) the development of visual speech perception – lip-reading and visual influence in auditory–visual integration; (ii) the development of auditory speech perception and native language perceptual attunement; and (iii) the relationship between these and a language skill relevant at this age, receptive vocabulary. Visual speech perception skills improved even over this relatively short time period. However, regression analyses revealed that vocabulary was predicted by auditory-only speech perception, and native language attunement, but not by visual speech perception ability. The results suggest that, in contrast to infants and schoolchildren, in three- to four-year-olds the relationship between speech perception and language ability is based on auditory and not visual or auditory–visual speech perception ability. Adding these results to existing findings allows elaboration of a more complete account of the developmental course of auditory–visual speech perception.

Studies investigating the development of tense/aspect in children with developmental disorders have focused on production frequency and/or relied on short spontaneous speech samples. How children with developmental disorders use future forms/constructions is also unknown. The current study expands this literature by examining frequency, consistency, and productivity of past, present, and future usage, using the Speechome Recorder, which enables collection of dense, longitudinal audio-video recordings of children's speech. Samples were collected longitudinally in a child who was previously diagnosed with autism spectrum disorder, but at the time of the study exhibited only language delay [Audrey], and a typically developing child [Cleo]. While Audrey was comparable to Cleo in frequency and productivity of tense/aspect use, she was atypical in her consistency and production of an unattested future form. Examining additional measures of densely collected speech samples may reveal subtle atypicalities that are missed when relying on only few typical measures of acquisition.

Preschoolers’ vocabulary acquisition sets the stage for later reading ability and school achievement. This study examined the role of socioeconomic status (SES) and the quality of the home environment of seventy-seven Chilean majority and Mapuche minority families from low and lower-middle-class backgrounds in explaining individual differences in vocabulary acquisition of their three-and-a-half-year-old children. Additionally, we investigated whether the relation between SES and receptive and expressive vocabulary was mediated by the quality of the home environment as the Family Investment Model suggests. The quality of the home environment significantly predicted receptive and expressive vocabulary above and beyond ethnicity, SES, parental caregiver status, and quantity of daycare. Furthermore, the quality of the home environment mediated the relation between SES and expressive and receptive vocabulary acquisition.

Several studies have found that, after repeated exposure to new words, children form orthographic representations that allow them to read those words faster and more fluently. However, these studies did not take into account variables related to the words. The aim of this study was to investigate the influence of sublexical variables on the formation of orthographic representations of words by Spanish children. The first experiment used pseudo-words of varying syllabic structure and syllabic frequency. The stimuli for the second experiment were formed with or without context-dependent graphemes. We found that formation of orthographic representations was influenced by syllabic structure (easier for words with simple syllabic structure) and the context-dependency of graphemes (easier in the absence of context-dependent graphemes), but not syllabic frequency. These results indicate that the easier it is to read a word, the easier it is to form an orthographic representation of it.

Children tend to regularize their productions when exposed to artificial languages, an advantageous response to unpredictable variation. But generalizations in natural languages are typically conditioned by factors that children ultimately learn. In two experiments, adult and six-year-old learners witnessed two novel classifiers, probabilistically conditioned by semantics. Whereas adults displayed high accuracy in their productions – applying the semantic criteria to familiar and novel items – children were oblivious to the semantic conditioning. Instead, children regularized their productions, over-relying on only one classifier. However, in a two-alternative forced-choice task, children's performance revealed greater respect for the system's complexity: they selected both classifiers equally, without bias toward one or the other, and displayed better accuracy on familiar items. Given that natural languages are conditioned by multiple factors that children successfully learn, we suggest that their tendency to simplify in production stems from retrieval difficulty when a complex system has not yet been fully learned.

We explored whether supported (SJE) or coordinated joint engagement (CJE) between mothers recruited from the community and their 24-month-old children who were slow-to-talk at 18 months old were associated with child language scores at ages 24, 36, and 48 months (n = 197). We further explored whether SJE or CJE modified the concurrent positive associations between maternal responsive behaviours and language scores. Previous research has shown that SJE, maternal expansions, imitations, and responsive questions were associated with better language scores. Our main finding was that SJE but not CJE was consistently positively associated with 24- and 36-month-old expressive and receptive language scores, but not with 48-month-old language scores. SJE modified how expansions and imitations, but not responsive questions, were associated with language scores; the associations were evident in all but the highest levels of SJE. Further research is necessary to test these findings in other samples before clinical recommendations can be made.

Speech disfluencies can guide the ways in which listeners interpret spoken language. Here, we examined whether three-year-olds, five-year-olds, and adults use filled pauses to anticipate that a speaker is likely to refer to a novel object. Across three experiments, participants were presented with pairs of novel and familiar objects and heard a speaker refer to one of the objects using a fluent (“Look at the ball/lep!”) or disfluent (“Look at thee uh ball/lep!”) expression. The salience of the speaker's unfamiliarity with the novel referents, and the way in which the speaker referred to the novel referents (i.e., a noun vs. a description) varied across experiments. Three- and five-year-olds successfully identified familiar and novel targets, but only adults’ looking patterns reflected increased looks to novel objects in the presence of a disfluency. Together, these findings demonstrate that adults, but not young children, use filled pauses to anticipate reference to novel objects.

Despite the fact that many of the world's languages use lexical tone, the majority of language acquisition studies has focused on non-tone languages. Research on tone languages has typically investigated well-known tone languages such as Mandarin and Cantonese Chinese. The current study looked at a Limburgian dialect of Dutch that uses lexical pitch differences, albeit in a rather restricted way. Using a visual habituation paradigm, 6- to 12-month-old Limburgian and Dutch infants were tested for their ability to discriminate Limburgian tones. The results showed that both Limburgian and Dutch infants discriminate the Limburgian tones throughout their first year of life. The role of linguistic experience, acoustic salience, and the degree of similarity to the native prosodic system are discussed.

Two studies assess French-speaking children's comprehension of object filler–gap dependencies, with the goal of investigating whether the degree of specificity/set-restriction of the fronted object or the intervening subject modulates comprehension. We tease apart the predictions of various accounts attributing children's difficulties to (i) similarities between the object and the intervening subject (Gordon et al., 2001, 2004), particularly when both constituents share a structural +NP feature (Friedmann et al., 2009); (ii) increased processing cost determined by an operation of set-restriction (Goodluck 2010); and (iii) the tendency to incrementally interpret sentences and the subsequent difficulty in revising an early commitment to an agent/subject-first analysis (Trueswell et al., 1999). Our results support the incremental processing view as they reveal that only a less specific fronted object, but not a less specific intervener, enhances comprehension. This suggests that referentially ambiguous objects alleviate children from an erroneous initial interpretive commitment to an agent/subject-first structure.

Word segmentation plays a crucial role in language acquisition, particularly for word learning and syntax development, and possibly predicts later language abilities. Previous studies have suggested that this ability develops differently across languages, possibly affected by the languages’ rhythmic properties (Rhythmic Segmentation Hypothesis) and target word location in the prosodic structure (Edge Hypothesis). The present study investigates early word segmentation in a language, European Portuguese, that exhibits both stress- and syllable-timed properties, as well as strong cues to both higher-level prosodic boundaries and the word level. Infants aged 4–10 months old were tested with target words located in utterance-medial and utterance-final positions. Evidence for word segmentation was found early in development but only for utterance-edge located target words, suggesting the more salient prosodic cues play a crucial role. There was some evidence for segmentation in utterance-medial position by 10 months, demonstrating that this ability is not yet fully developed, possibly due to mixed rhythmic properties.

In languages with evidential marking, utterances consist of an informational content and a specification of the mode of access to that information. In this first longitudinal study investigating the acquisition of the Turkish evidential marker −mIş in naturalistic child–caregiver interactions, we examined six children between 8 and 36 months of age. We charted individual differences in child and caregiver speech over time by conducting growth curve analyses. Children followed a similar course of acquisition in terms of the proportion of the marker in overall speech. However, children exhibited differences with respect to the order of emergence of different evidential functions (e.g., inference, hearsay), where each child showed a unique pattern irrespective of the frequency in caregiver input. Nonfactual use of the marker was very frequent in child and caregiver speech, where high-SES caregivers mostly produced the marker during story-telling and pretend play, and low-SES caregivers for regulating the child's behavior.

Production studies show connective acquisition by age 3;0, but comprehension studies show errors until 9;0 or older. To further investigate this gap, two comprehension tasks were carried out with 78 Dutch children between the ages of 7;0 and 10;1, testing contrastive maar ‘but’ and causal want ‘because’ connectives for comparison. An existing context choice task and a task that tested children's ability to interpret pronouns dependent on the connective were used. Children did well on the context choice task for want ‘because’, but performed far below chance with maar ‘but’. In the pronoun interpretation task the youngest children performed at or near chance with both connectives, but show gradual improvement with age. Task complexity may partially explain the results but in general, they are consistent with previous experiments showing contrastive connective comprehension is acquired very late compared to their correct production. Further, the pronoun interpretation task may give a more accurate picture of understanding.

Maternal responsive and directive speech to children at ages 0;10 and 2;0 was investigated by applying a procedure first introduced by Flynn and Masur (2007) to a new language community (Finnish). The issues examined were consistency and stability over time, and also the role of responsiveness and directiveness in child linguistic development at 1;0 and 2;6. The measures of maternal speech from each age were used to predict the results of the subsequent linguistic assessment. Negative correlations between responsive and directive utterances were found at both ages. The frequencies of responsive utterances and supportive directives increased over time. Responsiveness was positively, and intrusive directiveness negatively, related to child early comprehensive skills and the use of symbolic actions and communicative gestures. By contrast, no relations were found between responsiveness and directiveness and children's later linguistic capacities.

Vocabulary input frequency influences age of acquisition, and is also an essential control for investigating the influence of other factors. We propose a new method of frequency estimation, self-report. 918 Danish-speaking parents of 12–36-month-old children estimated their frequency of use of 725 words. Self-report was substantially correlated with both language sample based frequencies (0.67) and frequencies of a large written corpus of Danish (0.58). Correlations within vocabulary categories between frequency and age of acquisition, restricted to words occurring in the language samples, were comparable for the two estimates. Overall, self-report based frequency estimates appear to have a promising degree of validity, which reflects their greatest strength, independence of the situation.

When engaged in conversation, both parents and children tend to re-use words that their partner has just said. This study explored whether proportions of maternal and/or child utterances that overlapped in content with what their partner had just said contributed to growth in mean length of utterance (MLU), developmental sentence score, and vocabulary diversity over time. We analyzed the New England longitudinal corpus from the CHILDES database, comprising transcripts of mother–child conversations at 14, 20, and 32 months, using the CHIP command to compute proportions of utterances with overlapping content. Rates of maternal overlap, but not child overlap, at earlier time-points predicted child language outcomes at later time-points, after controlling for earlier child MLU. We suggest that maternal overlap plays a formative role in child language development by providing content that is immediately relevant to what the child has in mind.

To determine whether the developing semantic lexicon varies with culture, we examined the animal and food naming of children from three communities distinguished by language, cultural heritage, and population density. The children were five- and seven-year-olds from Australia (n = 197), Taiwan (n = 456), and the US (n = 172). Naming patterns revealed hierarchical and flexible organization of the semantic lexicon. The content of the lexicon, particularly food names, varied with cultural heritage. In all three communities, wild mammals were predominant during animal naming, a likely influence of children's media. The influence of the Chinese zodiac was evident in the clustering of animal names in the Taiwanese sample. There was no apparent influence of population density and little influence of language, except that the Taiwanese children more frequently named foods at the superordinate level, a possible influence of the structure of Mandarin. Children develop their lexicons in response to culture as experienced first-hand or through media.

This study investigated how speaker certainty (a rational cue) and speaker benevolence (an emotional cue) influence children's willingness to learn words in a selective learning paradigm. In two experiments four- to six-year-olds learnt novel labels from two speakers and, after a week, their memory for these labels was reassessed. Results demonstrated that children retained the label–object pairings for at least a week. Furthermore, children preferred to learn from certain over uncertain speakers, but they had no significant preference for nice over nasty speakers. When the cues were combined, children followed certain speakers, even if they were nasty. However, children did prefer to learn from nice and certain speakers over nasty and certain speakers. These results suggest that rational cues regarding a speaker's linguistic competence trump emotional cues regarding a speaker's affective status in word learning. However, emotional cues were found to have a subtle influence on this process.