Aspectual and mood morphology are vulnerable domains in adult heritage speakers. This paper investigates the root of such vulnerability within the domain of Turkish evidentiality system by comparing 20 second-generation adult and 20 school-age child Turkish heritage speakers to 20 first-generation immigrants (main input providers for child…

When linguistic input contains inconsistent use of grammatical forms, children produce these forms more consistently, a process called "regularization." Deaf children learning American Sign Language from parents who are non-native users of the language regularize their parents' inconsistent usages. In studies of artificial languages…

The words in children's language learning environments are strongly predictive of cognitive development and school achievement. But how do we measure language environments and do so at the scale of the many words that children hear day in, day out? The quantity and quality of words in a child's input are typically measured in terms of total amount…

Children acquire language in conversation. This is where they are exposed to the community language by more expert speakers. This exposure is effectively governed by adult reliance on pragmatic principles in conversation: Cooperation, Conventionality, and Contrast. All three play a central role in speakers' use of language for communication in…

This longitudinal study examined the development of narrative micro- and macrostructure in Japanese-English bilingual returnee children. Returnees are children of immigrant families who move to a foreign country, spending a significant portion of their formative developmental years in the foreign majority language context before returning to their…

This study investigated the predictions of two approaches to second language acquisition. According to the usage-based approach, learner knowledge results from the strengths and weaknesses of input-driven statistical learning. According to the learner-varieties approach, pragmatic communication principles and language-internal constraints play…

A recurring question in the literature of heritage language acquisition, and more generally of bilingual acquisition, is whether all linguistic domains are sensitive to input reduction and to cross-linguistic influence and to what extent. According to the Interface Hypothesis, morphosyntactic phenomena regulated by discourse-pragmatic conditions…

Many children diagnosed with autism spectrum disorder who receive early intervention reap developmental benefits, but little is known about characteristics of early intervention placements in the community that optimize individual growth. The extent to which children hear and use language, in particular, may contribute significantly to…

The unique relation of language use (i.e., output) to language growth was investigated for forty-seven 30-month-old Spanish-English bilingual children (27 girls, 20 boys) whose choices of which language to speak resulted in their levels of English output differing from their levels of English input. English expressive vocabularies and receptive…

As the traditional toys of the past are quickly being replaced with electronically "enhanced" toys, it is important to understand how these changes impact parent--child interactions, especially in light of the evidence that the richness and variety of these interactions have long-term effects on diverse areas of cognition (Hart &…

This study investigated how forty-six mothers modified their talk about familiar and unfamiliar nouns and verbs when interacting with their children with Down Syndrome (DS), language impairment (LI), or typical development (TD). Children (MLUs < 2·7) were group-matched on expressive vocabulary size. Mother-child dyads were recorded playing with…

In recent decades, a growing number of children have been diagnosed with autism spectrum disorder (ASD), a condition characterized by social interaction deficits and language impairment. Yet the precise nature of the disorder's impact on language development is not well understood, in part because of the language variability among children across…

Pitch is often described metaphorically: for example, Farsi and Turkish speakers use a "thickness" metaphor (low sounds are "thick" and high sounds are "thin"), while German and English speakers use a height metaphor ("low", "high"). This study examines how child and adult speakers of Farsi,…

Indigenous children growing up in the remote regions of Australia live in multilingual communities which are often undergoing rapid language shift. In these communities, children are exposed to a range of language input, including the traditional language of the area, a local creole and Standard Australian English. The extent to which the…

The present study investigates flexibility of verb use in the early stages of English multiword development, and its relationship with patterns attested in the input. The data is taken from a case study of a monolingual English-speaking boy aged 2; 5-2; 9 and his mother while engaged in daily activities in the home. Data were coded according to…