It is widely recognised that teachers' professional development is greatly enhanced through their participation in professional discourse. Professional discourse is a structured form of professional conversation that is widely used in lesson analysis and pre and post-lesson conferencing, within the contexts of mentoring and peer review. In Hong Kong, lesson observation and analysis also arise when conducting Learning Study. In these various contexts, conversation often turns on reconciling different interpretations and understandings of classroom events. When conducting a lesson (teacher talk) and in pre and post-lesson analysis (teacher conversation), meanings are not simply articulated, they are also created. Moreover, the meanings expressed by teachers when both teaching and analysing lessons are not stable; they are in process and change over time. The paper will outline these ideas in detail, with particular emphasis on lesson conferencing, building on the work previously undertaken by one of the authors on the hermeneutics of professional discourse. The conceptual framework discussed in the paper will provide the basis of a research programme that will shortly be undertaken in Hong Kong, as a component of a major government sponsored project conducting Learning Studies in both primary and secondary schools.