This talk explores repetition during L2 instruction as a ‘seen-but-unnoticed’ (i.e., common and taken-for-granted) element produced by students and teachers, who exhibit, recognize and 'trust' in this phenomenon (i.e., repetition) as a fundamental part of the organizational architecture of L2 classroom environments. We will explore some video-recorded data gathered in Portuguese language classes for beginner-level university students and discuss how the phenomenon of repetition is produced in that context as an instructionally relevant (and observable) practice. The analysis is divided into two parts. The first one refers to repetition in the third turn of the IRF sequence (Initiation-Response-Feedback). The second part refers to repetition as a resource to display moments of understanding of apprehensible objects, an action that reflexively produces pairs of categories such as [native speaker-non-native speaker] and [teacher-student]. The results point to two directions: 1) the need for empirical data to carry out an investigation on language classroom practices, since the phenomenon observed here is displayed by the participants as their in situ accomplished tasks; 2) the combination of sequential and categorial elements of talk in the production of the organization of repetition, which helps analysts avoid to take as ‘unproblematic’ the categorization work produced by classroom participants.