This longitudinal study - conducted in the Midwestern United States - examines the child-level factors that promote Spanish-English bilingual toddlers' (n = 47; M[subscript age] = 18.80 months; SD[subscript age] = 0.57) productive vocabulary skills from 18 to 30 months of age. At 6-month intervals, caregivers reported on toddlers' Spanish and…

Many children grow up hearing multiple languages, learning words in each. How does the number of languages being learned affect multilinguals' vocabulary development? In a pre-registered study, we compared productive vocabularies of bilingual (n = 170) and trilingual (n = 20) toddlers aged 17-33 months growing up in a bilingual community where…

Vocabulary size is a crucial early indicator of language development, for both monolingual and bilingual children. Assessing vocabulary in bilingual children is complex because they learn words in two languages, and there remains significant controversy about how to best measure their vocabulary size, especially in relation to monolinguals. This…

There is a well-documented link between bilingual language development and the relative amounts of exposure to each language. Less is known about the role of quality indicators of caregiver-child interactions in bilingual homes, including caregiver input diversity, warmth and sensitivity. This longitudinal study examines the relation between…

Previous work indicates mutual exclusivity in word learning in monolingual, but not bilingual toddlers. We asked whether this difference indicates distinct conceptual biases, or instead reflects best-guess heuristic use in the absence of context. We altered word-learning contexts by manipulating whether a familiar- or unfamiliar-race speaker…

Previous research indicates that developmental contexts influence language development. These developmental contexts include bilingualism, which is the focus of the current paper. This study analyses the influence that the acquisition of a language, Catalan, has when the simultaneous acquisition of another similar language, Spanish, occurs. This…

We examined the size, content, and use of evaluative lexis by 26 English monolingual and 20 Spanish-English bilingual 30-month-old children in interaction with their mothers. We extracted the evaluative words, defined as words referring to cognition, volition, or emotion. Controlling for overall vocabulary skills as measured by the MacArthur-Bates…

In this article, we present an analysis of the complexity of grammatical constraints and their impact on early language acquisition of inflectional morphemes in Malayalam. We use the natural speech production data of two monolingual children acquiring Malayalam between the ages 1;9-2;10 and 2;3-3;0 and three bilingual children acquiring…

Most words spoken to infants are produced in larger units, such as clauses, phrases, and sentences. As such, language learners must recognize words amidst the words that surround them. However, the phonetic forms of words change based on surrounding context. Here, we investigate the effects of a common source of phonetic change--phonological…

In bilingual language environments, infants and toddlers listen to two separate languages during the same key years that monolingual children listen to just one and bilinguals rarely learn each of their two languages at the same rate. Learning to understand language requires them to cope with challenges not found in monolingual input, notably the…

Most children learn a language such as Mandarin Chinese that uses lexical tone to communicate meaning. This study aimed to examine the phonological specificity of tone representations in monolingual and bilingual learners of Mandarin. Two age-groups were tested: toddlers (2.5 to 3.5 years) and preschoolers (4 to 5 years; N = 80). Using a…

An experimental crossover research design was utilized to investigate the effects of multimedia-enhanced instruction on the vocabulary acquisition of dual language learners in the early childhood age range. Sixteen 3-year-olds stratified by classroom and randomly assigned to condition participated in an eight-week intervention that incorporated…

Using a large sample of longitudinal assessment data from children in publicly funded infant/toddler care, preschool, and kindergarten (analytic N = 453,468), this study modeled language and literacy trajectories from early infancy through kindergarten for dual language learners (DLLs) from homes representing many different languages and their…

Is noun dominance in early lexical acquisition a widespread or a language-specific phenomenon? Thirty Singaporean bilingual English-Mandarin learning toddlers and their mothers were observed in a mother-child play interaction. For both English and Mandarin, toddlers' speech and reported vocabulary contained more nouns than verbs across book…

Children learn the words of their native language(s) from interactions with their caregivers. Although previous research has found that the language children hear during those interactions predicts vocabulary outcomes, few studies have investigated how qualitative features of social interactions work together to affect children's vocabulary…