Child-directed speech: relation to socioeconomic status, knowledge of child development and child vocabulary skill.

This study sought to determine why American parents from different socioeconomic backgrounds communicate in different ways with their children. Forty-seven parent-child dyads were videotaped engaging in naturalistic interactions in the home for ninety minutes at child age 2;6. Transcripts of these interactions provided measures of child-directed speech. Children's vocabulary comprehension skills were measured using the Peabody Picture Vocabulary Test at 2;6 and one year later at 3;6. Results indicate that: (I) child-directed speech with toddlers aged 2;6 predicts child vocabulary skill one year later, controlling for earlier toddler vocabulary skill; (2) child-directed speech relates to socioeconomic status as measured by income and education; and (3) the relation between socioeconomic status and child-directed speech is mediated by parental knowledge of child development. Potential mechanisms through which parental knowledge influences communicative behavior are discussed.