Annual Review of Applied Linguistics, 38 (2018), pp. 60–79. © Cambridge University Press, 2018 doi: 10.1017/S0267190518000119 Language Use Across International Contexts: Shaping the Minds of L2 Speakers J UDITH F. K ROLL University of California, Riverside judith.kroll@ucr.edu PAOLA E. D USSIAS Pennsylvania State University pdussias@psu.edu M ARÍA T ERESA B AJO University of Granada mbajo@ugr.es ABSTRACT Bilingualism is a complex life experience. Second language (L2) learning and bilin- gualism take place in many different contexts. To develop a comprehensive account of dual-language experience requires research that examines individuals who are learning and using two languages in both the first language (L1) and second language (L2) environments. In this article, we review studies that exploit the presence of an international research network on bilingualism to investigate the role of the environ- ment and some the unique characteristics of L2 learning and bilingual language usage in different locations. We ask how the context of learning affects the acquisition of the L2 and the ability to control the use of each language, how language process- ing is changed by the patterns of language usage in different places (e.g., whether bilinguals have been immersed in the L2 environment for an extended period of time or whether they code-switch), and how the bilingualism of the community itself influences learning and language use. Forms of language use across international contexts shape the minds of second language (L2) speakers. In much of the research on L2 learning and bilingualism, there has been a focus on how individuals might achieve a high level of proficiency in each of the languages that they speak. For adults, in particular, the issue of whether there are constraints that might impede or facilitate learning an L2 has shaped the field. Traditional accounts of language learning assumed that early in life there is openness to language input and exposure, but that beyond early childhood, there is a narrowing of sensitivity that requires alternative means to achieve proficiency (e.g., Clahsen & Felser, 2006; Johnson & Newport, 1989; Lenneberg, 1967; Piske, MacKay, & Flege, 2001). In the last two decades, the traditional account has been revised. In part, the assumption of hard constraints on adult language learning has been challenged by recent studies that exploit the tools of neuroscience to demonstrate widespread plasticity in learning across the life 60 https://doi.org/10.1017/S0267190518000119 Published online by Cambridge University Press