This chapter explores the framework for discourse analysis that applies to verbal conversations, conversations with world, and conversations with video games. Teachers and students behave in different ways in different schools, within different practices, and at different times in history. Being a teacher of a certain sort or being a student of a certain sort are social identities or avatars. The syntax here is the grammar of English as it functions in "teacher talk". Teacher talk is a style of language used in schools to carry out the purposes and tasks of formal schooling in certain ways. This universe of discourse includes things like desks, tests, grades, drill-sheets, report cards, homework, and routine practices and so forth. This universe of discourse is determined by the history of schooling and by public policies and shared cultural and social norms about schooling.