The effects of maternal input on language in the absence of genetic confounds: Vocabulary development in internationally adopted children

An observational study of parental language during play and mealtime in toddlers at variable likelihood for autism

Parental language input influences child language outcomes but may vary based on certain characteristics. This research examined how parental language differs during two contexts for toddlers at varying likelihood of autism based on their developmental skills. Parental language (quantity, quality, and pragmatic functions) was analyzed during dyadic play and mealtime interactions as a secondary data analysis of observational data from a study of toddlers at elevated and lower likelihood of autism. Child developmental skills and sensory processing were also assessed. Parents used more words per minute, directives, and verbs during play and more adjectives, descriptions, and questions during mealtime. Parental language differed based on child fine motor skills, receptive language, and levels of sensory hyporesponsiveness but not autism likelihood. Overall, this study found that parental language varies based on context and child developmental skills. Future research examining parental language should include pragmatic functions and context across developmental trajectories.

Hamrick L, Marklund E, Kalashnikova M, Guez A, Casillas M, Benetti L, van Alphen P, Cristia A. Everyday language input and production in 1,001 children from six continents

Language is a universal human ability, acquired readily by young children, who otherwise struggle with many basics of survival. And yet, language ability is variable across individuals. Naturalistic and experimental observations suggest that children's linguistic skills vary with factors like socioeconomic status and children's gender. But which factors really influence children's day-to-day language use? Here, we leverage speech technology in a big-data approach to report on a unique cross-cultural and diverse data set: >2,500 d-long, child-centered audio-recordings of 1,001 2- to 48-mo-olds from 12 countries spanning six continents across urban, farmer-forager, and subsistence-farming contexts. As expected, age and language-relevant clinical risks and diagnoses predicted how much speech (and speech-like vocalization) children produced. Critically, so too did adult talk in children's environments: Children who heard more talk from adults produced more speech. In contrast to previous conclusions based on more limited sampling methods and a different set of language proxies, socioeconomic status (operationalized as maternal education) was not significantly associated with children's productions over the first 4 y of life, and neither were gender or multilingualism. These findings from large-scale naturalistic data advance our understanding of which factors are robust predictors of variability in the speech behaviors of young learners in a wide range of everyday contexts.

Not just quantity but also quality of language: Cross-cultural comparisons of maternal mental state talk in New Zealand, Australia, and China

Western mothers use more mental state talk with children than do Chinese mothers (e.g., "think", "like", "happy"). The present study aimed to examine whether Western mothers not only produced a greater amount of mental state talk, but also used a wider range of mental state terms (i.e., greater lexical variety) compared to Chinese mothers. We compared maternal mental state talk in 271 mother-child dyads from New Zealand, Australia and China, and coded both quantity (i.e., frequency) and quality (i.e., type, variety, valence) of mothers' mental state talk to their 2.5- to 5-year-olds. Western mothers produced more talk about cognitions and emotions, as well as modulations of assertions, but a similar amount of desire talk, compared to Chinese mothers, with the same patterns found in the variety of talk. Western mothers produced an overall higher amount of mental state talk and a greater variety of mental state terms, but crucially, still produced more MS talk after controlling for the variety. Neither the amount nor the variety of maternal MS talk was correlated with children's theory of mind. These findings shed light on the diverse ways that mothers construe and describe mental states in different cultures, and highlight the importance of examining different aspects of maternal mental state talk and their impact on children's theory of mind in future longitudinal studies.