Measures of early social communication and vocabulary production to predict language outcomes at two and three years in late-talking toddlers

Background: Late talkers are a heterogeneous group of toddlers and reliable predictors of persistent language delay have been elusive. The purpose of this study was to determine the extent to which early social communication and vocabulary production predicted variance in language outcomes at 2 and 3 years of age. Methods: Participants were 408 typically developing and late-talking toddlers who completed the Communication and Symbolic Behavior Scales Caregiver Questionnaire and Behavior Sample (CSBS CQ and CSBS BS) at a mean of 20 months, the Language Development Survey (LDS) at a mean of 24 months, and the Mullen Scales of Early Learning (MSEL) at a mean of 25 months. A subgroup of 198 children completed a second MSEL at 3 years of age. Associations among the LDS, CSBS CQ, CSBS BS, and MSEL were examined using correlational and hierarchical linear regression analyses. Logistic regression was used to examine each measure\u27s contribution to predicting language delay at 2 and 3 years. Results: Moderate to large correlations were observed among all variables. The LDS, CSBS CQ, and CSBS BS added unique contributions to the prediction of 2- and 3-year expressive and receptive language outcomes. Measures of speech and vocabulary production were the strongest predictors of language outcomes at age 2. At age 3, social and symbolic communication played a more significant role in accounting for variance in expressive and receptive language outcome. A similar pattern emerged for the categorical prediction of language delay. Conclusions: Measures of social communication between 18–21 months added important information to predicting language outcomes at 2 and 3 years, above and beyond parent-reported expressive vocabulary production measured at 24 months, with small effect sizes overall. Implications for identifying younger children who are at risk for continued language delay and recommendations for referral to early intervention programs are discussed