The writers describe how apparently ordinary decisions about what to say when talking with children can have substantial effects on their learning and development. The language we use with children influences, among other things, who they think they are, what they think they're doing, the relationships they have with others, the strategic information available to them in the classroom, and the possibilities available to them for thinking about literacy and their own lives. The writers offer some principles for the kind of talk that helps build learning communities, engagement, a sense of agency, social relations, self-regulation and even moral development.