Although vocabulary size is thought to index children's language abilities, an increasing body of work suggests that regularities in children's vocabulary composition, particularly the proportion of shape-based nouns (e.g., cup), support language development. Here we examine initial vocabulary composition in children with hearing loss following…

Over half of US children are enrolled in preschools, where the quantity and quality of language input from teachers are likely to affect children's language development. Leveraging repeated objective measurements, we examined the rate per minute and phonemic diversity of child and teacher speech-related vocalizations in preschool classrooms and…

How do children construct a concept of natural numbers? Past research addressing this question has mainly focused on understanding how children come to acquire the cardinality principle. However, at that point children already understand the first number words and have a rudimentary natural number concept in place. The question therefore remains;…

The toddler and preschool years are a time of significant development in both expressive and receptive communication abilities. However, little is known about the neurobiological underpinnings of language development during this period, likely due to difficulties acquiring functional neuroimaging data. Functional near-infrared spectroscopy (fNIRS)…

Associative word learning, i.e., associating a word with an object, is an important building block of early word learning for TD infants. This study investigated the development of word-I object associations by TD infants and infants and toddlers with Williams syndrome (WS), a rare genetic disorder associated with delayed language and cognitive…

While we know that interventions targeting oral language can be effective, little is known about what drives these effects. In this study, we examine whether gains in transfer measures are mediated through the specific words that are trained in a language intervention. Based on a large-scale randomized controlled trial of language intervention in…

Word segmentation is a fundamental aspect of language learning, since identification of word boundaries in continuous speech must occur before the acquisition of word meanings can take place. We previously used functional magnetic resonance imaging (fMRI) to show that youth with autism spectrum disorder (ASD) are less sensitive to statistical and…

Children's gesture production precedes and predicts language development, but the pathways linking these domains are unclear. It is possible that gesture production assists in children's developing word comprehension, which in turn supports expressive vocabulary acquisition. The present study examines this mediation pathway in a population with…

What aspects of infants' prelinguistic communication are most valuable for learning to speak, and why? We test whether early vocalizations and gestures drive the transition to word use because, in addition to indicating motoric readiness, they (a) are early instances of intentional communication and (b) elicit verbal responses from caregivers. In…

Children learn words by listening to caregivers, and the quantity and quality of early language input predict later language development. Recent research suggests that word recognition efficiency may influence the relationship between input and vocabulary growth. We asked whether language input and lexical processing at 28-39 months predicted…

To what extent do toddlers have shared vocabularies? We examined CDI data collected from 14,607 infants and toddlers in five countries and measured the amount of variability between individual lexicons during development for both comprehension and production. Early lexicons are highly overlapping. However, beyond 100 words, toddlers share more…

In many low- and middle-income countries, young children learn a mother tongue or indigenous language at home before entering the formal education system where they will need to understand and speak a country's official language(s). Thus, assessments of children before school age, conducted in a nation's official language, may not fully reflect a…

We investigated whether fine motor and expressive language skills are related in the later-born siblings of children with autism (heightened-risk, HR infants) who are at increased risk for language delays. We observed 34 HR infants longitudinally from 12 to 36 months. We used parent report and standardized observation measures to assess fine motor…

We examined gestural and verbal interactions in 226 mother-infant pairs from Mexican, Dominican, and African American backgrounds when infants were 14 months and 2 years of age, and related these interactions to infants' emerging skills. At both ages, dyads were video-recorded as they shared a wordless number book, a wordless emotion book, and…

This paper presents follow-up longitudinal data to research that previously suggested the possibility of abnormal gaze behavior marked by decreased eye contact in a subgroup of 6-month-old infants at risk for autism (Merin, Young, Ozonoff & Rogers, 2007). Using eye-tracking data and behavioral data recorded during a live mother-infant interaction…