This study compared the speech of fathers and mothers to young children in the age ranges of 19-29-months and 32-43-months. Audio tape recordings were made of the verbal interactions of 20 father-daughter dyads and 20 mother-daughter dyads while engaged in free play in the family home. Using verbatim transcripts of the sessions, the degree of parental speech modification as a function of the age and linguistic production capactities of the child was assessed. The results indicated that both fathers and mothers adjust certain aspects of their speech relative to both age and linguistic production skills. In addition, very similar patterns of speech adjustment were found for mothers and fathers. Specifically, parents of both sexes adjusted the length of their utterances as a function of the production capacity of the child and moderated the concreteness and diversity of their vocabulary relative to the age and production skills of the child with whom they were interacting. (Author/MP)