In this preregistered, longitudinal study of early code-switching, 34 US-born, Spanish-English bilingual children were recorded with a bilingual family member at 2;6 and 3;6, in Spanish-designated and English-designated interactions. Children's Spanish and English expressive vocabulary and their exposure to code-switching were measured through…

Many children learn language, in part, from the speech of non-native speakers who vary in their language proficiency. To investigate the influence of speaker proficiency on the quality of child-directed speech, 29 mothers who were native English speakers and 31 mothers who were native speakers of Spanish and who reported speaking English to their…

From a socio-cultural perspective, language offers a means for children to communicate with and learn from others through interaction: language is the medium through which young children are provided cognitive, social, and emotional support in interactions with caregivers, siblings, and peers; and children characterized as dual language learners…

This study examined the linguistic and individual-level factors that render case marking a vulnerable domain in English-dominant Greek heritage children. We also investigated whether heritage language (HL) children can use case-marking cues to interpret (non-)canonical sentences in Greek similarly to their monolingual peers. A group of six- to…

This study examines language mixing in 26 Spanish-English dual language learners over the course of their first year of preschool. The children's patterns of language choice while interacting in monolingual language contexts were analyzed at age 3;6 and 4;5 to examine: (1) whether the frequency of language mixing changed during the year; (2)…

The Cross-linguistic Lexical Task (CLT; Haman, Luniewska & Pomiechowska, 2015) is a vocabulary task designed to enable cross-linguistic comparisons both across and within (bilingual) children. In this paper we assessed the validity of the CLT as a measure of language proficiency in bilingual children, by determining the extent to which: (1)…

Several aspects of early language skills, including parent-report measures of vocabulary, phoneme discrimination, speech segmentation, and speed of lexical access predict later childhood language outcomes. To date, no studies have examined the long-term predictive validity of novel word learning. We examined whether individual differences in novel…

This study investigated the durational features of English word-initial /s/+stop clusters produced by bilingual Mandarin (L1)-English (L2) children and monolingual English children and adults. The participants included two groups of five- to six-year-old bilingual children: low proficiency in the L2 (Bi-low) and high proficiency in the L2…

Children are thought to learn second languages (L2s) using primarily implicit mechanisms, in contrast to adults, who primarily rely on explicit language learning. This difference is usually attributed to cognitive maturation, but adults also receive more explicit instruction than children, which may influence their learning strategies. This study…

To achieve language proficiency, infants must find the building blocks of speech and master the rules governing their legal combinations. However, these problems are linked: words are also built according to rules. Here, we explored early morphosyntactic sensitivity by testing when and how infants could find either words or within-word structure…

Past research suggests that bilingualism positively affects children's performance in false belief tasks. However, researchers have yet to fully explore factors that are related to better performance in these tasks within bilingual groups. The current study includes an assessment of proficiency in both languages (which was lacking in past work)…

When bilingual children enter formal reading education, host language proficiency becomes increasingly important. This study investigated the relation between socioeconomic status (SES), maternal language use, reading input, and vocabulary in a sample of 111 six-year-old children of first- and second-generation Turkish immigrant parents in the…

Children categorize native-accented speakers as local and non-native-accented speakers as foreign, suggesting they use accent (i.e., phonological proficiency) to determine social group membership. However, it is unclear if accent is the strongest--AND ONLY--group marker children use to determine social group membership, or whether other aspects of…

The current study examined monolingual English-speaking toddlers' (N=50) ability to learn word-referent links from native speakers of Dutch versus English, and second, whether children generalized or sequestered their extensions when terms were tested by a subsequent speaker of English. Overall, children performed better in the English than in the…

Children with SLI have difficulty with tense and agreement morphology. This study examined the proficiency of these children and their typically developing peers with the coordination of tense and aspect markers in two-clause sentences. Scenarios designed to elicit past tense were presented to five- to eight-year-old children with SLI (n = 14) and…