This paper reports the design and trial of an original Observational Framework for quantitative investigation of young children's responses to adult language in their typical language learning environments. The Framework permits recording of both the response expectation of the adult utterances, and the degree of compliance in the child's responses. The former are evaluated under the categories of Response Required (RR), Response Not Required (RNR), and Other Directed (OD) spoken to a child other than the one who responds); the latter, based on both verbal and non-verbal behaviours, as Compliance (correct in the context), Valid (correct in another context), Ambiguous (unable to be classified), Acknowledgement, Inappropriate and No Response. Details are given for the initial application of the Observational Framework with 10 children in two- or three-year-old childcare centre classrooms. The findings that RR utterances in the adult input were more frequently addressed to younger children, while RNR utterances were more prevalent in the older classroom are discussed in terms of both adult and child communicative behaviours and the practicality of using the Observational Framework in naturalistic conditions. (Contains 6 tables.)