An analysis of utterances made by children and teachers in Norwegian day care centers over a period of several years suggests that from a communicative and functional viewpoint, young children's use of language depends on: (1) the kind of play activitiy; and (2) the preschool teacher's participation and language, which reflects her attitude and personality. In general, frequent use of the four types of utterance examined (intellectual, instructive, socio-emotional, and dialogue-supporting) was associated with more active participation in playgroup interaction. The activity of role-playing promotes these speech acts and implies a higher proportion of communicative utterances. While these activities can not be called teaching, they may be educational and do imply that learning is occurring. Young children and those with poor communication skills appear to improve their language use and social behavior through role-playing. Two main types of preschool teacher language were identified: a language of teaching (either for subject teaching or language instruction) and a language of ordinary adult-child communication. Further research into the educational effects of these two language types may illuminate children's cognitive development. A brief bibliography is included. (MSE)