Resumen

Background: orchestrating classroom communication is one of the challenges for teachers in exploratory lessons. Objectives: we aim to understand how the participation of secondary school teachers in a lesson study based on an exploratory approach promotes the development of their knowledge about classroom communication. Design: the research is qualitative and interpretative. Setting and participants: the participants are three secondary school teachers who were willing to participate. Data collection and analysis: data were collected through participant observation (with research journal and audio/videorecording), document collection, and a focus group interview. Results: during the students’ autonomous work, although with different actions, closed progress details and open progress initiatives, the teachers listened to small-group discussions and used them as a starting point to support the students, asking them to explain their answers without pointing out the strategy to follow, according to what they discussed in the planning sessions. During the wholeclass discussion, the teachers promoted the comparison of different representations and invited the students to explain and justify their answers, as they had planned, but also considered answers that they did not anticipate. After observing the research lesson, the teachers reflected about the students’ explanations, valuing their clarity, and referring to them as an opportunity for the teacher to understand how the students were thinking. Conclusions: the results suggest that lesson study is a professional development process in which secondary school teachers can deepen their knowledge about classroom communication.