A longitudinal study of the relationship between early language development and play development.

Temporal correspondences between the attainment of specific milestones in play and language were examined through a longitudinal study of four Japanese children (aged 0;7 to 0;11 at the beginning of the study). There were developmental correspondences between the onset of six language landmarks (the emergence of first words, naming words, vocabulary spurts, word-chains, nonproductive two-word utterances, productive two-word utterances) and the onset of subcategories of play. Language and play both reflected the development of underlying symbolic ability, and both developed in parallel manner at the single-word stage. After the emergence of word-chains, language and play developed interdependently. All the children proceeded through the same sequence of stages, but the rate of development was different depending on their environment.