This book is about the prospect of a social turn in the field of second language acquisition (SLA) and in particular that part of SLA which is devoted to the Input-Interaction-Output model. The overall aim of the book is to examine critically some of the basic notions and assumptions that underpin this model and to suggest a more interdisciplinary and socially informed approach to SLA research.

In order to achieve this aim, I subject the elements making up the acronym SLA to close scrutiny, analysing what mainstream SLA researchers understand by 'second', 'language' and 'acquisition'. Drawing on recent work in sociolinguistics, as well as SLA research influenced by sociolinguistic and sociohistorical approaches to language and language learning, I argue that there is a need for a less partial view of what SLA is about and a broadening of horizons to take on board this work.

The book begins with an introductory chapter in which I argue that SLA should follow the lead of sociolinguistics and applied linguistics, where in recent years researchers have begun to work in a more socially informed and interdisciplinary manner. This chapter is followed by a short history of SLA in which I make the case that SLA has come together as a field of academic endeavour over the past forty years and that the Input-Interaction-Output model is by far the most ambitious, well developed and productive area of research in SLA today. Then, in Chapters 3–5, I discuss in detail and analyse what is generally meant by the 'S', the 'I' and the 'O' in SLA, with a specific focus on the Input-Interaction-Output model. Along the way, I make suggestions for how these concepts might be examined in a more socially informed and interdisciplinary fashion. I end the book with some speculations about the future of SLA research.