Infants' sensitivity to transitional probabilities (TPs) supports language development by facilitating mapping high-TP (HTP) words to meaning, at least up to 18 months of age. Here we tested whether this HTP advantage holds as lexical development progresses, and infants become better at forming word--referent mappings. Two groups of 24-month-olds…

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…

Infants' preference for vowelharmony (VH, a phonotactic constraint that requires vowels in a word to be featurally similar) is thought to be language-specific: Monolingual infants learning VH languages show a listening preference for VH patterns by 6 months of age, while those learning non-VH languages do not (Gonzalez-Gomez et al., 2019; Van…

Exposure to communicative gestures, through their parents' use of gestures, is associated with infants' language development. However, the mechanisms supporting this link are not fully understood. In adults, sensorimotor brain activity occurs while processing communicative stimuli, including both spoken language and gestures. Using…

Early exploratory behaviors have been proposed to facilitate children's learning, impacting motor, cognitive, language, and social development. This study related the performance of behaviors used to explore oneself to behaviors used to explore objects, and then related both types of exploratory behaviors to motor, language, and cognitive measures…

The current study examined early grammatical marking in a relatively understudied language, Mandarin, by using the Mandarin version of MacArthur-Bates Communicative Development Inventory. Two waves of data collection included 338 monolingual children (17-36 months; 143 female) at Time 1 and 308 children (32-55 months; 139 female) at Time 2 and…

The interplay between self-regulation related skills and language is well recognized in dynamic theories, but few empirical studies have tested it, especially in toddlers. The current study examines the bidirectional links between self-regulation related skills and expressive vocabulary in a longitudinal study during toddlerhood. Participants were…

Research suggests foster children are at risk for poor language skills. One intervention, attachment and biobehavioral catch-up (ABC), was shown to successfully improve not only young foster children's attachment to their parents, but also their receptive vocabulary skills (Bernard et al., 2017; Raby et al., 2019). Given that language acquisition…

The ability to categorize emotions has long-term implications for children's social and emotional development. Therefore, identifying factors that influence early emotion categorization is of great importance. Yet, whether and how language impacts emotion category development is still widely debated. The present study aimed to assess how labels…

Why do infants learn some words earlier than others? Many theories of early word learning focus on explaining how infants map labels onto concrete objects. However, words that are more abstract than object nouns, such as "uh-oh," "hi," "more," "up," and "all-gone," are typically among the first to…

Upon hearing a novel label, listeners tend to assume that it refers to a novel, rather than a familiar object. While this disambiguation or mutual exclusivity (ME) effect has been robustly shown across development, it is unclear what it involves. Do listeners use their pragmatic and lexical knowledge to exclude the familiar object and thus select…

A significant body of literature has demonstrated that infants demonstrate a decline in sensitivity to nonnative sound contrasts by their first birthday, a transition often thought to be adaptive for later word learning. The present study investigated infants' sensitivity to these contrasts in a habituation-based discrimination and word learning…

To examine whether children's acquisition of perspective-marking language supports development in their ability to reason about mental states, we conducted a longitudinal study testing whether proficiency with complement clauses around age 3 explained variance in false-belief reasoning 6 months later. Forty-five English-speaking 2- and 3-year-olds…

Children all over the world learn language, yet the contexts in which they do so vary substantially. This variation needs to be systematically quantified to build robust and generalizable theories of language acquisition. We compared communicative interactions between parents and their 2-year-old children (N = 99 families) during mealtime across…

As they develop into mature speakers of their native language, infants must not only learn words but also the sounds that make up those words. To do so, they must strike a balance between accepting speaker-dependent variation (e.g., mood, voice, accent) but appropriately rejecting variation when it (potentially) changes a word's meaning (e.g., cat…