Learning a language in a formal context is not the same as learning a language in a natural setting, in that the goal of one of the participants in the communicative events that occur in the classroom, the teacher, is to teach a language. For this reason, the majority of the actions undertaken by the participants are directed at achieving that goal. That is why observing and analyzing interaction in the classroom becomes a key element in understanding how we learn. This chapter sets out ways this issue is approached through conversation analysis. The transcription symbols used in this chapter are based on conventions developed by the GREIP group (see Moore & Llompart, this volume) and are included in the annex. [A Catalan version of this chapter is also included in the book. For the complete volume, "Qualitative Approaches to Research on Plurilingual Education," see ED573580.]