This study focuses on the modes of interaction that are being established in a classroom. We discuss specifically the case of children that do not speak to adults. Aided by the theories of enunciation, by Bakhtin's dialogism and by Discourse Analysis, we examine some theoretical alternatives to study interaction and silence. The study of events related to silence, conceived as moments of interaction, leads us to explore the relationship between these terms and to consider their implications for teacher's work in the classroom.