Previous studies have found correlations between parent input and child language outcomes, providing prima facie evidence for a causal relation. However, this could also reflect the effects of shared genes. The present study removed this genetic confound by measuring English vocabulary growth in 29 preschool-aged children (21 girls) aged…

Children acquire language embedded within the rich social context of interaction. This paper reports on a longitudinal study investigating the developmental relationship between conversational turn-taking and vocabulary growth in English-acquiring children (N = 122) followed between 9 and 24 months. Daylong audio recordings obtained every 3 months…

This study investigated the relation between Dual Language Learners' (N = 90) vocabulary and grammar comprehension and word learning processes in preschool (aged 3-through-5 years). Of interest was whether: (a) performance in Spanish correlated with performance in English within each domain; and (b) comprehension predicted novel word learning…

This study investigates the impact of evidentiality on source monitoring and the impact of source monitoring on false belief understanding (FBU), while controlling for short-term memory, age, gender, and receptive vocabulary. One hundred (50 girls) monolingual 3- and 4-year-olds from Turkey and the UK participated in the study in 2019. In Turkish,…

In this study, infant vocabulary development was tracked in a multilingual society (Singapore) within a socioeconomically diverse sample. The sample comprised 1316 infants from 17.4 to 27.7 months (669 females, 647 males; 88% Chinese race, 4% Malay, 4% Indian, and 0.004% mixed-race [4% declined to provide race information]). Children varied in…

When and how do infants learn color words? It is generally supposed that color words are learned late and with a great deal of difficulty. By examining infant language surveys in British English and 11 other languages, this study shows that color word learning occurs earlier than has been previously suggested and that the order of acquisition of…

Although the size of a child's vocabulary associates with language-processing skills, little is understood regarding how this relation emerges. This investigation asks whether and how the structure of vocabulary knowledge affects language processing in English-learning 24-month-old children (N = 32; 18 F, 14 M). Parental vocabulary report was used…

Significant differences in language and self-regulation skills exist among children when they enter formal schooling. Contributing to these language differences is a growing population of dual language learners (DLLs) in the United States. Given evidence linking self-regulatory processes and language development, this study explored bidirectional…

In the world, the manners and paths of motion events take place together, but in language, these features are expressed separately. How do infants learn to process motion events in linguistically appropriate ways? Forty-six English-learning 7- to 9-month-olds were habituated to a motion event in which a character performed both a manner and a…

Fundamental to amassing a lexicon of relational terms (i.e., verbs, prepositions) is the ability to abstract and categorize spatial relations such as a figure (e.g., "boy") moving along a path (e.g., "around" the barn). Three studies examine how infants learn to categorize path over changes in "manner," or how an action is performed (e.g., running…

This study examined whether 12-month-olds will accept words that differ phonologically and phonetically from their native language as object labels in an associative learning task. Sixty infants were presented with sets of English word-object (N = 30), Japanese word-object (N = 15), or Czech word-object (N = 15) pairings until they habituated.…

This longitudinal study examined growth in the English productive vocabularies of bilingual and monolingual children between ages 24 and 36 months and explored the utility and validity of supplementing parent reports with teacher reports to improve the estimation of children's vocabulary. Low-income, English-speaking and English/Spanish-speaking…

Examined whether infants succeed in mapping novel adjectives applied ostensively to individual objects and to other objects with the same property. Found that infants hearing a target labeled with novel adjectives were more likely than those hearing no novel words to choose a matching test object when all objects were drawn from same basic level…

Despite the prevalence of bilingualism, language acquisition research has focused on monolingual infants. Monolinguals cannot learn minimally different words (e.g., "bih" and "dih") in a laboratory task until 17 months of age ( J. F. Werker, C. T. Fennell, K. M. Corcoran, & C. L. Stager, 2002). This study was extended to 14- to 20-month-old…

Analyzed vocalizations/verbalizations from children acquiring English or French in later single-word period to identify trochaic bias. Found that neither language's vocalizations were exclusively trochaic. French/English differences in iambic productions and acoustic realization of accent were traceable to adult input. Distribution of trochaic and…