Abstract
<jats:title>Abstract</jats:title> <jats:p>We learn languages in and through interaction. Given the central role of interaction in learning (and teaching), analysis of interaction has become an object of scientific inquiry since the earliest days of second/additional language (L2) learning and teaching research. Analysis of interaction has also become a source and drive for methodological innovation. In this chapter, I unpack the components, contexts, and dimensions of interaction within the broader field of L2 learning and teaching. The review of previous research presented in this chapter shows that the analysis of interaction paves the way to the broadening of knowledge about interaction that extends beyond the domain of oral communication skills, as the study of interaction is a gateway to understanding broader processes involved in language learning and teaching. The depth and quality of the analysis of the interaction between learners or between teachers and learners offer valuable insights into the learning of formal aspects of language and the development of a set of competencies (e.g., interactional competence) in L2. Going beyond language learning, the analysis of interaction during teaching also offers insights into teaching methodologies and curriculum, with implications for a wide spectrum of areas in applied linguistics.</jats:p>