The present research focused upon responses of three- and four-year old children to communicative demands posed in four common kinds of question situations. There were also manipulations of the object about which the question was asked, to test dependence of young children upon the presence of such objects. Children's responses were scored for two kinds of appropriateness to situational demands: (1) of grammatical constructions employed, and (2) of communicative functions which the response accomplished. Results were as follows: Three-year-olds made more errors of function than did four-year-olds, but there were no age differences in errors of grammar. Age differences in function errors were greater in more difficult manipulations both of question situation and context manipulation than in less difficult conditions. Open-ended and explanatory questions produced more errors, both of grammar and function than did yes-no and labeling questions. Open-ended situations produced more errors of grammar than explanatory situations, while explanatory situations produced the greatest number of errors of function. Context-object manipulations altered only numbers of errors of function in three-year-olds. The results indicate that the child constantly acquires not only linguistic knowledge but also pragmatic knowledge which enables him to use language functionally. (Author/DB)