Talking Mathematics in School investigates the relationship between students' discussions about mathematics in K-12 classrooms and their mathematical understanding. Beginning with a linguistic and sociolinguistic review of what is known about connections between thought, language, and learning, Lampert and Blunk consider what this research suggests for the teaching and learning of mathematical ideas and discourse. A collection of studies from various disciplinary perspectives--set in elementary and secondary classrooms, a computer-supported tutorial, and a workplace interaction--examines the nature of mathematical talk and the roles of students, teachers, tasks, and environment in producing it.