Early bilingualism of many young children is characterized by an apparent mixture of languages. Because of the variety of patterns they follow and the lack of empirical data available it is difficult to make generalizations. However, the speech of individual children can be examined for insights into early bilingualism. To this purpose, a study was undertaken of a child who seemed to have no constraints on language mixing and/or code switching. The child was videotaped at the age of 2 years 11 months in a two hour spontaneous play session at a bilingual nursery school. The tapes were transcribed and the child's utterances were counted to determine the number of utterances in each language and in each language situation. The transcribed data were analyzed according to mean length of utterance, conversational analysis, and syntax. Analysis of all the data indicated that the child's speech was neither an indiscriminate nor a random mixture. His English and Spanish were found to be consistent with the language of monolingual English- and Spanish-speaking children at the same level of development. The interpretation of the results is that the child uses a mixed code because of his language environment; it is a question of rules for language use rather than of language development. (AMH)