Examined in a longitudinal study of children were correspondences and correlations between early language development on the one hand, and the manipulation of objects and play development on the other. There were developmental correspondences between the onset of five language landmarks (the emergence of first word, referential word, demonstrative pronoun, word-chains and two-word utterances) and the onset of subcategories of manipulation of objects and play. These correspondences were compared with the predictions proposed by McCune-Nicolich (1981, 1986) concerning the development of language and symbolic play. Language and the manipulation of objects and play were found to reflect the development of underlying symbolic ability, and develop in parallel at the single-word stage. After the emergence of word-chains, they develop interdependently. (Author/PCB)