Language Experiences and Vocabulary Development in Dominican and Mexican Infants Across the First 2 Years

We longitudinally investigated parental language context and infants ’ language experiences in relation to Dominican American and Mexican American infants ’ vocabularies. Mothers provided information on parental language context, comprising measures of parents ’ language background (i.e., childhood language) and current language use during interviews at infants ’ birth. Infants ’ language experiences were measured at ages 14 months and 2 years through mothers ’ reports of mothers ’ and fathers’ engagement in English and Spanish literacy activities with infants and mothers ’ English and Spanish utterances during videotaped mother–infant interactions. Infants ’ vocabulary development at 14 months and 2 years was examined using standardized vocabulary checklists in English and Spanish. Both parental language context and infants ’ language experiences predicted infants ’ vocabularies in each language at both ages. Furthermore, language experiences mediated associations between parental language context and infants ’ vocabularies. However, the specific mediation mechanisms varied by language