Differential responding to two- and three-year-olds' utterances: the roles of grammaticality and ambiguity.

Mothers have been found to respond differently to grammatical and ungrammatical utterances in young children's language. However, parents indicate that they are conscious only of responding to communicative aspects of their children's speech, not grammar. Further, researchers have looked to the understandability of utterances to explain the effects of grammaticality on maternal responses. The present study addressed the question of whether it is actually grammatical form that mothers respond to, or whether it is ambiguity in the communicative functions of children's utterances. Three mother-child dyads were videotaped in a free play setting when the children were 2;0 and 3;0. Children's spontaneous comprehensible utterances were rated for grammaticality and ambiguity of function, and mothers' responses to them were noted. Results indicated that mothers responded differentially to both the ambiguity and grammaticality of children's utterances, and that these two factors had some degree of independence in their effects on mothers' responses.