Purpose: This longitudinal study assessed continuity and stability of productive language (vocabulary and grammar) and discourse features (turn-taking; asking and responding to questions) during mother-child play.
Method: Parent-child language use in 119 Spanish-speaking, Mexican immigrant mothers and their children at two ages (M = 2.5 and 3.6 years) was evaluated from transcriptions of interactions.
Results: Child productive language significantly increased over the year, whereas mothers showed commensurate increases in vocabulary diversity but very little change in grammatical complexity. Mother-child discourse was characterized by discontinuity: Mothers decreased their turn length and asked fewer questions while children increased on both measures. Rates of responding to questions remained high for both mothers and children even as children increased and mothers decreased over time. Mothers and children showed significant rank-order stability in productive language and measures of discourse. Mothers' rate of asking questions and children's responses to questions during the first interaction predicted children's receptive vocabulary a year later.
Conclusions: As children become more sophisticated communicators, language input remains important, with discourse features growing in relevance. Children's early opportunities to respond to parents' questions in the context of play benefit their language skills. This work extends the evidence base from monolingual English-speaking families and is interpreted in the context of prior research on parenting practices in U.S. families of Mexican origin.