To further investigate the possible regulatory role of private and inner speech in the context of referential social speech communications, a set of clear and systematically applied measures is needed. This study addresses this need by introducing a rigorous method for identifying private speech and certain sharply defined instances of inaudible inner speech. Using this classification system, longitudinal data were gathered from 10 pairs of children performing a referential communication task at 4.5, 6.5, and 8.5 years of age. Results demonstrated children's substantial production of private and inner speech in this communicative situation, with speech forms varying in amount and type as a function of age, communicative role (speaker or listener), and the complexity of the material to be communicated. It is suggested that private and inner speech embedded in discourse may serve a regulatory role in social speech communication. (Contains 4 tables.)