This qualitative study was concerned with examining the first language of young Mexicano bilinguals who had already learned enough English to work in all-English classrooms. In order to capture natural language usage within the school setting, five focal children were chosen, observed and audiotaped throughout their school day, for a period of roughly four months. This research presents data on the functions that Spanish continued to serve in the lives of these developing bilinguals. Additionally, it describes the competence they showed in their Spanish. Throughout their school day, in different roles, and in distinct contexts, the children used Spanish in varied and complex ways: (a) to provide information and assistance with school work; (b) to seek explanations, information and clarification; (c) to provide their own self-talk which helped them think through problems, plan strategies and assess their own work; d) to establish and maintain a variety of social relationships, juggling changes in ...