Trying to improve communication skills: the challenge of joint sense making in classroom interactions

International audience; In this paper we examine the efforts of one teacher working to improve her students' communication skills as part of a collaborative project with teachers and teacher educators/researchers. The paper reports on a project meeting where the teacher presents a short video clip featuring two student explanations. Yet only one explanation is treated in the lesson as an example of good communication. Following discussion and multiple re-viewings of the video clip in the meeting, what counts as good communication is critiqued by the teachers. Driven by an emphasis on the two-way nature of communication, the need for joint sense-making between teacher and students, and privileging explanations that communicate mathematical understanding, alternative teacher actions are suggested during the meeting that are related to how different teachers interpreted the students' explanation.