The present paper reports on the phonological form of one child's productive vocabulary from age 0;10 to 1;8 with primary focus on his production of multisyllabic targets. A large percentage of his multisyllabic vocabulary was produced as one syllable until the age of 1;6. This limitation was not due to a tendency to extract only single syllables from the speech stream, but rather due primarily to a limitation on production. While some portion of his one-syllable productions could be interpreted as the result of single syllable extraction, a sizeable portion affirmed that he extracted the target size correctly by his inclusion of first and final target phonemes in his productions (e.g. [po] for piano and [kiz] for candies). The resolution of this limitation coincides with his move toward two-word speech. We conclude that there is a developmental and perhaps maturational limitation in the capacity to carry out the processes underlying word and sentence production.

This study compared segmental distribution patterns for consonants and vowels in English infant-directed speech (IDS) and adult-directed speech (ADS). A previous study of Korean indicated that segmental patterns of IDS differed from ADS patterns (Lee, Davis & MacNeilage, 2008). The aim of the current study was to determine whether such differences in Korean are universal or language-specific. Results indicate that consonant distribution patterns of English IDS were significantly different from English ADS. Speakers who used IDS produced fewer fricatives, affricates, nasals and liquids, but more stops and glides, than speakers who used ADS. In terms of vowels, IDS speakers produced more high-back vowels /u Ʊ/ and /ɔI/ diphthongs than ADS speakers. These results indicate both general trends and language-specific segmental distribution patterns in IDS. When compared to previous findings on ADS and IDS in Korean, these results for English give support to a more general assertion that segmental distribution patterns in IDS seem to be mediated by linguistic and cultural factors across languages.

Children's ability to learn and retain new words is fundamental to their vocabulary development. This study examined word retention in children learning a home language (L1) from birth and a second language (L2) in preschool settings. Participants were presented with sixteen novel words in L1 and in L2 and were tested for retention after either a 2-month or a 4-month delay. Results showed that children retained more words in L1 than in L2 for both of the retention interval conditions. In addition, children's word retention was associated with their existing language knowledge and their fast-mapping performance within and across language. The patterns of association, however, were different between L1 and L2. These findings suggest that children's word retention might be related to the interactions of various components that are operating within a dynamic system.

This study examined 32 children’s (M age=1;8 years) engagement in joint attention (JA) and the relation between JA and vocabulary size across mother–child (MC) and mother–child–sibling (MCS) contexts. In the MCS context, mothers engaged in JA more with one child than both children; they engaged in less JA with target child than they did in the MC context. JA style was generally unrelated across the contexts. Coordinated JA and children’s vocabulary were significantly related only for the MCS context. Findings suggest the number of social partners influences JA dynamics and multi-child contexts can be positive language learning environments.

This paper investigates whether three-year-olds are able to process attributive adjectives (e.g., soft pillow) as they hear them and to predict the noun (pillow) on the basis of the adjective meaning (soft). This was investigated in an experiment by means of the Visual World Paradigm. The participants saw two pictures (e.g., a pillow and a book) and heard adjective–noun combinations, where the adjective was either informative (e.g., soft) or uninformative (e.g., new) about the head-noun. The properties described by the target adjectives were not visually apparent. When the adjective was uninformative, the looks at the target increased only upon hearing the noun. When the adjective was informative, however, the looks at the target increased upon hearing the adjective. Three-year-olds were as fast as adult controls in predicting the upcoming noun. We conclude that toddlers process adjective–noun phrases incrementally and can predict the noun based on the prenominal adjective.

Cross-linguistic influence (CLI) refers to the linguistic influence of one of a bilingual's languages while processing the other. Researchers have debated whether CLI is better explained by the structure of bilinguals' two languages or by a combination of processing demands and structure. In this study, we test if Welsh–English bilingual children manifest CLI when producing adjectival constructions. Welsh adjectives typically appear postnominally, English adjectives typically appear prenominally. Since these structures do not overlap, there may be no CLI. If, however, CLI is a result of competition between languages, children's adjectival constructions may be reversed in both languages. We elicited adjectival constructions from Welsh–English bilingual children and English monolingual children between three and six years of age. The bilingual children produced more reversals than monolinguals and equivalent rates of reversals in both languages. In other words, the results support an interpretation of CLI resulting, at least in part, from processing demands.

In the literature on phonological acquisition certain strategies such as homonymy and reduplication are viewed as phenomena appearing at a very early age, resulting from a deficient sound-inventory and sound-distribution. Data on homonymy and reduplication from a longitudinal study will be considered, which show that: (a) such strategies can appear later in the child's linguistic development than it has been proposed; (b) the lexical item has to be considered a central unit, beyond the earliest stages, in the acquisition of phonology.

It is commonly believed that first-learned words correspond with first-learned categories (both described as ‘basic level’) leading to the belief that language acquisition is a reasonably good indicator of early cognition. However, toddlers often overextend their first words. Do these errors reflect their comprehension? Two experiments were conducted in order to examine two-year-olds' production and comprehension of basic-level terms. The results showed overextensions both in production (e.g. children labelled a rocket ‘airplane’) and comprehension (e.g. they pointed to a rocket when airplane was requested). One reason toddlers extend labels to a wider conceptual domain is because they have not clearly differentiated basic-level concepts from related conceptual categories.

In two sentence repetition experiments, we investigated whether four- and five-year-olds master distinct representations for intransitive verb classes by testing two syntactic analyses of unaccusatives (Burzio, 1986; Belletti, 1988). Under the assumption that, with unaccusatives, the partitive case of the postverbal argument is realized only on indefinites (Belletti, 1988), we tested whether children used indefiniteness as a feature to assign the partitive case to the verb's argument. In the sentences, we manipulated whether the subject preceded or followed the (unaccusative or unergative) verb and whether the subject was expressed by means of a definite or indefinite NP. With unaccusatives, children tended to place the subject in the postverbal position when the subject NP was indefinite, whereas, when the sentence presented a definite postverbal subject, children preferred to place the definite subject in the preverbal position. Definiteness exerted an effect only with unaccusatives, suggesting that children treated unergatives and unaccusatives differently.

In this work, we examine a context in which a conflict arises between two roles that infant-directed speech (IDS) plays: making language structure salient and modeling the adult form of a language. Vowel devoicing in fluent adult Japanese creates violations of the canonical Japanese consonant–vowel word structure pattern by systematically devoicing particular vowels, yielding surface consonant clusters. We measured vowel devoicing rates in a corpus of infant- and adult-directed Japanese speech, for both read and spontaneous speech, and found that the mothers in our study preserve the fluent adult form of the language and mask underlying phonological structure by devoicing vowels in infant-directed speech at virtually the same rates as those for adult-directed speech. The results highlight the complex interrelationships among the modifications to adult speech that comprise infant-directed speech, and that form the input from which infants begin to build the eventual mature form of their native language.

This study investigated how Turkish-speaking children and adults interpret negative sentences with disjunction (English or) and ones with conjunction (English and). The goal was to see whether Turkish-speaking children and adults assigned the same interpretation to both kinds of sentences and, if not, to determine the source of the differences. Turkish-speaking children and adults were found to assign different interpretations to negative sentences with disjunction just in case the nouns in the disjunction phrase were marked with accusative case. For children, negation took scope over disjunction regardless of case marking, whereas, for adults, disjunction took scope over negation if the disjunctive phrases were case marked. Both groups assigned the same interpretation to negative sentences with conjunction; both case-marked and non-case-marked conjunction phrases took scope over negation. The findings are taken as evidence for a ‘subset’ principle of language learnability that dictates children's initial scope assignments.

Adults use vision to perceive low-fidelity speech; yet how children acquire this ability is not well understood. The literature indicates that children show reduced sensitivity to visual speech from kindergarten to adolescence. We hypothesized that this pattern reflects the effects of complex tasks and a growth period with harder-to-utilize cognitive resources, not lack of sensitivity. We investigated sensitivity to visual speech in children via the phonological priming produced by low-fidelity (non-intact onset) auditory speech presented audiovisually (see dynamic face articulate consonant/rhyme b/ag; hear non-intact onset/rhyme: –b/ag) vs. auditorily (see still face; hear exactly same auditory input). Audiovisual speech produced greater priming from four to fourteen years, indicating that visual speech filled in the non-intact auditory onsets. The influence of visual speech depended uniquely on phonology and speechreading. Children – like adults – perceive speech onsets multimodally. Findings are critical for incorporating visual speech into developmental theories of speech perception.

This study investigates how phonological neighborhood density (PND) affects word production and recognition in 4-to-6-year-old Russian children in comparison to adults. Previous experiments with English-speaking adults showed that a dense neighborhood facilitated word production but inhibited recognition whereas a sparse neighborhood inhibited production but facilitated recognition. Importantly, these effects are not universal because a reverse PND pattern was found in Spanish-speaking adults. Probably, PND effects depend on the morphological properties of language.

This study focuses on PND effects in word production and recognition in terms of facilitation and inhibition in Russian. Our results are consistent with those in Spanish: Russian-speaking adults produced words with dense neighborhoods more slowly and recognized them faster than words with sparse neighborhoods. Russian children showed the same PND effect in recognition and no effect was found in production. The findings support the hypothesis that PND effects in word production and recognition are influenced by the morphological system of language.

The current study used a forced choice pointing paradigm to examine whether English children aged 2 ; 1 can use abstract knowledge of the relationship between word order position and semantic roles to make an active behavioural decision when interpreting active transitive sentences with novel verbs, when the actions are identical in the target and foil video clips. The children pointed significantly above chance with novel verbs but only if the final trial was excluded. With familiar verbs the children pointed consistently above chance. Children aged 2 ; 7 did not show these tiring effects and their performance in the familiar and novel verb conditions was always equivalent.

Despite growing research on individual differences in child bilinguals, few studies have focused on the development of syntax, included both languages, and studied newly arrived school-age migrant children. Accordingly, this study investigated the syntactic development of heritage language (HL) Syrian Arabic and L2 English by Syrian refugee children (N = 119) recently arrived in Canada using a sentence repetition task. Regression analyses showed that a partially overlapping set of child-level (input and cognitive skills) and language-level (syntactic structure) factors accounted for performance in each language. HL performance was particularly sensitive to language, cognitive, and input variables indexing cumulative HL exposure. L2 performance, however, was sensitive to cognitive and environmental variables indexing current and cumulative L2 use. Finally, despite stronger performance in Arabic than in English, results revealed interdependence between the two languages, indicating that participants with stronger syntactic abilities in their HL tended to have stronger syntactic abilities in their emerging L2.

This study investigates whether the earliest words children choose to say are mainly words containing sounds they can produce (cf. ‘phonological dominance’ hypotheses), or whether children choose words without regard to their phonological characteristics (cf. ‘lexical dominance’ hypotheses). Phonological properties of words in spontaneous speech from six children age 0;8 to 2;11 were analyzed by comparing sound distributions of consonant place and manner. Word-initial and word-final consonant patterns in children's Word Targets versus Actual Word Forms were analyzed as a function of vocabulary size. Word-initial results showed more overall evidence for phonological dominance. In word-final position, at lower vocabulary sizes, results showed several differences between Word Targets and Actual Word Forms, consistent with lexical dominance. These findings challenge an ‘either–or’ phonological versus lexical dominance approach, and support consideration of a multifactorial set of influences, including different phonological dimensions and word positions, on the words that young children choose to say.

Considerable research has demonstrated that English-speaking children extend nouns on the basis of shape. Here we asked whether the development of this bias is influenced by the structure of a child's primary language. We tested English- and Spanish-speaking children between the ages of 1 ; 10 and 3 ; 4 in a novel noun generalization task. Results showed that English learners demonstrated a robust shape-bias, whereas Spanish learners did not. Further, English-speaking children produced more shape-based nouns outside the laboratory than Spanish-speaking children, despite similar productive vocabulary sizes. We interpret the results as evidence that attentional biases arise from the specifics of the language environment.

Iconic words imitate their meanings. Previous work has demonstrated that iconic words are more common in infants’ early speech, and in adults’ child-directed speech (e.g., Perry et al., 2015; 2018). This is consistent with the proposal that iconicity provides a benefit to word learning. Here we explored iconicity in four diverse language development datasets: a production corpus for infants and preschoolers (MacWhinney, 2000), comprehension data for school-aged children to young adults (Dale & O'Rourke, 1981), word frequency norms from educational texts for school aged children to young adults (Zeno et al., 1995), and a database of parent-reported infant word production (Frank et al., 2017). In all four analyses, we found that iconic words were more common at younger ages. We also explored how this relationship differed by syntactic class, finding only modest evidence for differences. Overall, the results suggest that, beyond infancy, iconicity is an important factor in language acquisition.