Richer language experience leads to faster understanding [electronic resource] : links between language input, processing efficiency, and vocabulary growth

How do children's early environments influence the development of language skills known to be critical for later academic success? Three studies examine how the early language experiences of low-SES Latino children contribute to the development of their productive vocabulary and skill in interpreting spoken language, two critical aspects of language development. In Study 1, recordings of children's language environments over a typical day in the home revealed striking differences among families in the amount of talk directed to children. These differences in children's exposure to language were related to other aspects of their early environments, such as the amount of time they spent in different activities, the number of different adults and children with whom they interacted, and their exposure to electronic media. Importantly, the amount of talk that was directed to children, but not the amount of talk overheard by children, predicted children's vocabulary outcomes. Study 2 examined the development of children's efficiency in spoken language understanding, investigating potential causes of individual differences in language-processing skills as well as considering their consequences. Differences in infants' speech processing efficiency at 19 months predicted children's productive vocabulary at 24 months, such that those infants who were relatively faster and more reliable in interpreting familiar words early on were those with larger productive vocabularies 5 months later. These differences in children's language processing skills were linked to variability in early experience with language at home: Infants who experienced richer language input at 19 months were more efficient in real-time language processing at 24 months. But more importantly, differences in processing skill mediated the robust link between early language experience and later vocabulary. This suggests that language interactions with attentive caregivers help advance children's vocabularies by supporting the development of critical language-processing skills. In Study 3, differences in early language input predicted children's skill in inferring the referent of a novel label in an ambiguous context. Children who experienced richer language interactions at 19 months were more likely to map a novel word to a novel object at 32 months. This suggests that early language experience may support the development of word-learning skills, and thus further advance vocabulary growth. Together, these studies show that language experience has a pervasive influence on the development of children's language skills. On the one hand, they reveal the cost to children without rich language experiences at home, in terms of missed opportunities for learning. But they also suggest that increased opportunities for language interaction early in life have the potential to alter the course of language growth, with cascading advantages for children's academic and vocational outcomes.

Keywords: Psychology
Advisor: Fernald Anne
Clark Eve V. advisor. Thesis advisor
Markman Ellen M.