A study was conducted to investigate oral language used in fourth- and fifth-grade student dyads in a collaborative writing setting in order to understand better how children learn to write. The study was based on a theoretical framework that emphasized the interrelatedness of thought, language, and learning. Following a pilot study, students in five dyads were given three different writing assignments: composing a story with a prescribed ending sentence, writing a text on a topic of mutual interest, and writing individual responses to literature following discussion. The sessions were tape recorded and qualitatively analyzed in relation to researcher notes. The results indicated that oral language played an important role in (1) the maintenance of interpersonal relationships; (2) problem solving relative to the writing task; (3) exploration of language and of new ideas; and (4) critical examination of existing ideas. The nature of the writing assignment affected advanced planning, type of language used, and length of production. More sophisticated writers were more deliberative and engaged in more word play than less sophisticated writers. In addition, boys and girls exhibited consistent differences. Girls were concerned with feelings and personal values while boys focused on high-powered action. (HTH)