Drawing on recent socio-cultural approaches to research on language learning and an extensive corpus of classroom video recording made over four years, the book documents language learning as an epiphenomenon of peer face-to-face interaction. Advanced technology for recording classroom interaction (6 cameras per classroom) allows the research to move the focus for analysis off the teacher and onto learners as they engage in dyadic interaction. The research uses methods from conversation analysis with longitudinal data to document practices for interaction between learners and how those practices change over time. Language learning is seen in learners’ change in participation in their in social actions that occur around and within teacher-assigned language learning tasks (starting the task, non-elicited story tellings within tasks, and ending tasks). Web links are provided so the reader can see the data from the classroom that is the subject of the analyses.