A range of language use model is proposed as an alternative conceptual framework to a stage model of egocentric speech. The range of language use model is proposed to clarify the meaning of the term egocentric speech, to examine the validity of stage assumptions, and to explain the existence of contextual variation in the form of children's speech. The basic premise of this approach is that four forms of speech--private, social, egocentric, and socialized--coexist developmentally. Illustrative examples of each form of speech are given from tape recordings of natural conversations of the author and her daughters over a 5-year period (J. aged 4 to 9, and L. aged 1 to 6). The fundamental developmental assumption of a range of language use approach is that competence is a function of the interplay between a speaker who possesses certain intrinsic abilities and a context of language use that exerts specific demands on these abilities. It is assumed that there are developmental differences between adults and children in the range of contexts in which each can use language effectively. The distinctions between egocentric and private speech, and between social and socialized speech, provide a conceptual basis for resolving the interpretative controversy that resulted from the fusion in Piaget's 1926 theory of egocentric speech of the social-motivational and cognitive sources of breakdown in children's interpersonal communication. (Author/SS)