Noting that many instructional routines discourage complex thought and language, a study examined how teachers and children used language in the first 3 weeks in 3 preschools. Specifically it explored how teachers talk to children, what teachers ask children to do with language, and what children say in school. The language features of teacher-child and parent-child interaction were contrasted. Teachers use simplification techniques to direct and monitor a child's actions, and the child does not think or talk in complex ways, usually responding in fragments. In a transcribed videotaped interaction, 80 percent of a teacher's talk consisted of directing and monitoring, while 20 percent conveyed or elicited new information. In adult-child interaction, adults convey new information by describing and demonstrating, by explaining their thought processes, and by asking open-ended questions. Children also ask questions of adults. Both use complex language uttered in complete sentences. In a taped example, 60 percent of the utterances conveyed and elicited information. However, videotapes of classroom interaction during the first 3 weeks of school showed that the classroom teachers exhibited many of the behaviors of the single teacher-child interaction. Teacher-student interactions were asymmetrical, with students following the teacher's agenda. These characteristics suggest that many complex language functions from homes do not thrive at schools. (Transcripts and tables of complexity of videotaped interactions are included.) (TM)