DOI: 10.1111/weng.12300 ARTICLE Second Language Acquisition and world Englishes: Dialogue and engagement Peter I. De Costa Dustin Crowther Department of Linguistics and Germanic, Slavic, Asian and African Languages, Michigan State University, USA Correspondence Peter I. De Costa, Department of Linguistics and Germanic, Slavic, Asian and African Languages, Michigan State University, 619 Red Cedar Road, Wells Hall B257, East Lansing, MI 48823, USA. Email: pdecosta@msu.edu Abstract In spite of the explosive growth in the global use of English, the subfields of Second Language Acquisition and world Englishes have failed to establish a synergistic relationship that can pro- pel both areas of research forward well into the 21st century. In this pedagogically-oriented article, we survey how previously estab- lished barriers between these vibrant disciplines have begun to erode, and illustrate how increased dialogue between both streams can address real world problems through a contemporary recon- ceptualization of person, place, process, and multilingualism and modality. 1 INTRODUCTION As has been well attested in recent literature, an increase in global mobility and migration has inevitably led to a significant increase in communication occurring across boundaries (Appiah, 2006; Dervin, 2014; MacKenzie, 2011). More specifically, within these cross-cultural interactions, the strength of the English language as a world language has reached unprecedented heights of global importance (Jenkins, 2014; Seidlhofer, 2011; Trudgill, 2002). Often cited are the statistics proposed by Graddol (2006) and Crystal (2008), who have claimed that 75% of English speakers are now not only ‘nonnatives’ (NNSs) – equaling nearly two billion users – but that 75% of face-to-face English interactions are between NNSs. Despite this positioning of English as a global lingua franca, the two primary streams of research directly related to the use of English – Second Language Acquisition (SLA) 1 and world Englishes (WE) – have rarely worked in tandem, and often times have been in direct conflict. We argue in this pedagogically-oriented article that the increasing global spread of English has brought us to a point where it is vital to the advancement of both SLA and WE research that both sides recognize that: (1) previously established barriers have begun to erode; and (2) increased dialogue between both streams will in the long term better serve the interests of those who matter most – the global users of English 2 – and thus address real world problems (Kubota, this issue). After providing a brief overview of where WE and SLA research currently stands, we identify the general faultlines along which the two research agendas have traditionally been found to differ. We subsequently describe how recent theoretical innovations in both WE and SLA have allowed for the bridging of such gaps, highlighting specific themes in which WE and SLA research interests in fact converge. Out of these themes we will provide recommendations in how research stemming from a collaborative approach may inform contemporary English pedagogy. World Englishes 2018;37:19–33. wileyonlinelibrary.com/journal/weng c  2018 John Wiley & Sons Ltd 19