The purpose of this study was to determine whether the private speech of 40 kindergarten children involved in a problem-solving task differed according to gender, socioeconomic status, sociability, and academic ability. The introductory chapter provides a brief summary of the theoretical views of Piaget and Vygotsky concerning private speech. Chapter 2 reviews research on private speech and its relationship to such variables as intellectual maturity and sociability. Also discussed are the private speech of boys and girls and that of children from lower socioeconomic backgrounds. Chapters 3 through 5 deal with methodology, results, conclusions and recommendations. Private speech was categorized according to Manning and White's 4 levels and 13 sublevels. Findings support Vygotsky's theory in that children considered by teachers to be below-average in academic ability used more unhelpful private speech than did children considered to be above-average. There were no differences at any of the four levels in the private speech of male and female subjects, of children considered above- or below-average in sociability, or of children from middle- and lower-class families. It is concluded that teachers might identify students needing extra attention by listening to the private speech of their young students. (RH)