Information on language use patterns in bilingual classrooms is presented and analyzed in relation to the types of grouping decisions commonly made by teachers. The data were collected from two bilingual elementary classrooms and obtained through audio-recording and observation. Group setting contrasts of group size and instructional mode were established. The variables selected to measure language use were amount of talk, complexity of speech, and language functions, for which a speech act category system was adapted. It was concluded that group setting affects language use. Findings include: (1) the effect of group setting on language use is mediated by teaching style; (2) small group settings provide a highly favorable context for language use, (3) the range of speech acts was broader during individual work than during teacher-directed instruction, (4) the weaker language of all students was infrequently used in the classroom for natural communication, and (5) the weaker language fulfilled a variety of different functions. Tables present types and examples of speech act categories and quantitative analyses of amount of talk in the dominant and weaker language, the different speech acts performed in the dominant language, and the distribution of language functions in the weaker language. (JK)