Early Literacy Research Library (ELRL) - Article

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

Gilkerson, J., Richards, J.A., Warren, S.D., Oller, D.K., Russo, R., Vohr, B. (2018) Language Experience in the Second Year of Life Predicts Language Outcomes in Late Childhood. Pediatrics, 142(4), e20174276. ,

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Publication year


study description


core topic(s)

Early Literacy

Population Characteristics


Exposures, Outcomes, Other

Child Development (general) , Home Language/Literacy/Learning Environment , Parent-Child Relationships/Interactions , School Readiness and Educational Outcomes


This study tested the effectiveness of automated early language environment estimates for children 2–36 months to predict cognitive and language skills 10 years later and examined effects for specific age periods of early development.


Early talk and interaction at home.

outcomes evaluated

Early language and cognitive outcomes.


Children predominantly between 2–36 months of age (nine between 38–47 months) were recruited from the Denver-metro area, matching the US census on an SES proxy (mother’s attained education).


Daylong audio recordings for 146 infants and toddlers were completed monthly for 6 months, and the total number of adult words and adult-child conversational turns for recording days were automatically estimated with LENA software. Follow-up evaluations at 9–14 years of age included language and cognitive testing using the Wechsler Intelligence Scale for Children-Fifth Edition (WISC-V – IQ and Verbal Comprehension Index, VCI), Peabody Picture Vocabulary Test (PPVT), and Expressive Vocabulary Test (EVT). Language exposure for three age groups was assessed: 2–17, 18–24 and 25+ months. Pearson correlations and multiple linear regression analyses were conducted.

sample size

n=146 (infants and toddlers)


Measure of Early Talk and Interaction at Home: audio recordings processed via LENA software to quantify adult word exposure, child vocalization, and turn-taking interactions throughout the day based on algorithmic analysis.


Measure of Child Language Skills: averaged total expressive and receptive standard language scores from Preschool Language Scale-Fourth Edition and the Receptive Expressive Emergent Language Test-Third Edition.


Measure of Child’s Vocabulary Size: age-appropriate version of the MacArthur-Bates Communicative Development Inventory completed by parents.


Measures of Language and Cognitive Outcomes:

    • Wechsler Intelligence Scale for Children-Fifth Edition (WISC-V IQ and VCI)
    • Peabody Picture Vocabulary Test (PPVT)
    • Expressive Vocabulary Test (EVT)


Conversational turn counts at 18–24 months of age accounted for 14–27% of the variance in IQ, verbal comprehension, and receptive/expressive vocabulary scores ten years later, after controlling for SES. Adult word counts between 18–24 months correlated with language outcomes but were weakened after controlling for SES.


These data support the hypothesis that early talk and interaction, particularly during a relatively narrow developmental window of 18–24 months, predicts school-age language and cognitive outcomes. These findings underscore the need for early intervention programs that support parents to create an optimal early language learning environment in the home.


One limitation to these results is their correlational nature – although we refer to statistical predictiveness, we cannot infer causality. For example, other developmental changes occurring during the 18–24 months period may primarily account for cognitive and language skills later. Another limitation is that although the sample spanned a relatively large range of mother’s education levels, only 10 children were from the lowest SES group. In addition, the sample is not ethnically diverse and includes only monolingual English-speakers, so the generalizability of results to other languages and cultures is unknown.