Observation of play can provide crucial information about a child's developmental level of language. To make this information available categorization and measurement are necessary. By defining, from a cognitive and pragmatic point of view, separate but parallel measures of play and language it was possible to define four different levels of symbolic functioning: representational play; conceptual play; programmatic play; and script play. Careful longitudinal descriptions of language used to accompany symbolic play of ten 2-4-year-old children are presented. Interesting developmental trends in play and cognitive and pragmatic organization of language were found. Gradually language production was considered as the primary mode for symbolic expression between the ages of 2;6 (2 years; 6 months) and 3 years. Language production increased dramatically between the ages of 3 and 3;6, and became better differentiated from the play context. The scientific study of child language using an analytic tool, such as a play procedure, to describe and analyse spontaneous production of spoken language, with a cognitive and pragmatic framework contributes not only a more accurate understanding of normal play and language development, but may also have an efficient clinical value. Suggestions for and implications of exploring components of language used in a standardized play situation are discussed in reference to developmentally disabled children.