This volume offers insights on language learning outside the classroom, or in the wild, where L2 users themselves are the driving force for language learning. The chapters, by scholars from around the world, critically examine the concept of second language learning in the wild. The authors use innovative data collection methods (such as video and audio recordings collected by the participants during their interactions outside classrooms) and analytic methods from conversation analysis to provide a radically emic perspective on the data. Analytic claims are supported by evidence from how the participants in the interactions interpret one another's language use and interactional conduct. This allows the authors to scrutinize the term wild showing what distinguishes L2 practices in our different datasets and how those practices differ from the L2 learner data documented in other more controlled settings, such as the classroom. We also show how our findings can feed back into the development of materials for classroom language instruction, and ultimately can support the implementation of usage-based L2 pedagogies. In sum, we uncover what it is about the language use in these contexts that facilitates developmental changes over time in L2-speakers' and their co-participants' interactional practices for language learning.