Setting the stage for the central themes and the articles in this special issue, this introduction delineates the epistemological confluences, complementarities, and differences among conversation analysis (CA), on the one hand, and 2 strands of usage-based linguistics, on the other-namely, usage-based secondlanguage acquisition (SLA) and interactional linguistics. This implies depicting how an increased interest in actual usage within the field of linguistics, including usage-based SLA, has converged with the basic assumptions in CA and interactional linguistics: (a) Language use is primordially and primarily situated in social interaction, and (b) language emerges out of social interaction. We scrutinize the grounds for combining the 3 frameworks for investigating second language development, illustrate such combination through the discussion of some of the rare existing studies that integrate these frameworks, and argue for the need to develop the methodological combinations further in order to move toward an ecologically more valid understanding of how language develops out of language use. On that basis, and additionally drawing on the individual contributions to the special issue, we then outline some implications for L2 education.