Stability and predictive validity in the language and play development of 41 toddlers were studied. Links between language and symbolic play of toddlers were examined at 13 and 20 months in terms of homotypic, heterotypic, or mediated models of association. In the homotypic model, performance on a variable is related to performance on the same variable at a later time. In the heterotypic model, performance on one variable is related to performance on another variable concurrently or at a later time. Stability and predictive validity between two variables is explained by a third, remote, mediating variable in the mediating model. Both homotypic stabilities and heterotypic predictions in children's performance were identified. In most cases, associations between toddler abilities held after the introduction of covarying related aspects of maternal stimulation. This suggests that toddlers' representational competencies reflect shared underlying components rather than external mediation. Representational competence demonstrated stability across the second year. Results are discussed with respect to the componential structure of language and the implications of multidimensionality of mind for models of stability and prediction. Citations number 55. (Author/RH)