An analysis of classroom discourse proposes four frames, modeled as concentric circles. The inner most circle is the lesson frame, removed or sheltered from outside influences and most likely, in a language class, to maintain second-language usage. The next frame from the center is the lesson-support frame, an intermediate layer of classroom discourse aimed at clarifying talk, repairing miscommunication, maintaining discipline, and supporting on-task behavior. The third, institutional-support frame is that in which communication relating to the wider school agenda outside a particular class takes place. The outermost circle is the commentary frame, a frame for speaking in one's authentic voice as an individual or community member. This is the most permeable to outside influences relating to popular culture and vernacular language. The model of classroom communication is illustrated using data from Hong Kong classroom interactions in a secondary school English class with a Cantonese-speaking teacher and students. The different frames of communication and use of different codes (English, mixed, Cantonese) are analyzed. Contains 16 references. (MSE)