In this article, we reappraise the model of Discourse Analysis developed by Sinclair and Coulthard (1975) to analyse classroom talk. We analyse an extract of teacher–student dialogue using this model, then re-analyse the same extract drawing on conventions and concepts developed within the framework of Conversation Analysis. We argue that this more fine-grained perspective makes visible the co-constructed nature of teacher–student dialogue, and reveals improvisation strategies, such as the morality tale, used by the teacher to incorporate divergent points of view within the polyphony of classroom discussion. Our findings indicate the communicative importance of speech prosody in educational settings. We conclude by suggesting avenues for further research in the field and suggest possible applications of our perspective to the practice of classroom teaching and learning.