In a study of the significance of private speech, 11 learning disabled (LD) and 16 non LD children (mean age 10 years) were given several cognitive tasks, and their private speech during play and school work was assessed. LD Ss performed less well on the cognitive tasks than non LD Ss. Children who used high rates of private speech performed in a more immature manner on the cognitive tasks, supporting the notion that private speech is related to cognitive development and not just chronological age. When experimental conditions were varied, Ss talked more when alone in a room than when an adult was present, and they tended to talk more in academic-task than in play conditions. (Author/CL)