Language Experience in the Second Year of Life and Language Outcomes in Late Childhood

OBJECTIVES: Quantity of talk and interaction in the home during early childhood is correlated with socioeconomic status (SES) and can be used to predict early language and cognitive outcomes. We tested the effectiveness of automated early language environment estimates for children 2 to 36 months old to predict cognitive and language skills 10 years later and examined effects for specific developmental age periods. METHODS: Daylong audio recordings for 146 infants and toddlers were completed monthly for 6 months, and the total number of daily adult words and adult-child conversational turnswere automatically estimated with Language Environment Analysis software. Follow-up evaluations at 9 to 14 years of age included language and cognitive testing. Language exposure for 3 age groups was assessed: 2 to 17 months, 18 to 24 months, and >= 25 months. Pearson correlations and multiple linear regression analyses were conducted. RESULTS: Conversational turn counts at 18 to 24 months of age accounted for 14% to 27% of the variance in IQ, verbal comprehension, and receptive and/or expressive vocabulary scores 10 years later after controlling for SES. Adult word counts between 18 and 24 months were correlated with language outcomes but were considerably weakened after controlling for SES. CONCLUSIONS: These data support the hypothesis that early talk and interaction, particularly during the relatively narrow developmental window of 18 to 24 months of age, can be used to predict school-age language and cognitive outcomes. With these findings, we underscore the need for effective early intervention programs that support parents in creating an optimal early language learning environment in the home.