Group level and individual differences in second language sentence processing

Abstract Variability at the group and individual level can inform understanding in second language research. For example, examining by-group and individual differences can play an important role in teasing apart competing theoretical accounts of first and second language processing. In this paper, I review existing research examining variability in second language sentence processing. Focusing on relative clause attachment, filler-gap dependency resolution and subject-verb agreement, I examine these three phenomena as case studies for how examining variability can inform key debates in second language processing research. I review variability at the group and individual level in both cognitive and linguistic abilities, language experience and proficiency, and in the linguistic environment. I also discuss methodological issues in generalizing findings across studies and in using psycholinguistic tasks to examine individual variation in language processing, which pose important challenges that need to be addressed if the field is to move towards an individual differences perspective of second language processing. Although the review focuses on three linguistic phenomena in second language sentence processing, the issues discussed are relevant to the examination of variability in bi-/multilingual language acquisition and processing more broadly.