Available evidence shows that living outside the native language environment and being intensively exposed to L2 changes patterns of processing of both L2 and L1: not only enhances L2 proficiency but also limits access to L1 and thus modulates the way in which two languages of a bilingual interact with each other (e.g. Linck, Kroll, & Sunderman, 2009; Martin, 2011, Baus et al., 2013). In the present study, we investigated how L2 immersion modulates cross-language interference. We tested two groups of adult Polish-English bilinguals: 87 bilinguals living in the UK and experiencing immersion in their L2 and 85 bilinguals living in Poland, in their L1 environment.
All participants were tested with a set of behavioral tasks: Two semantic relatedness tasks with interlingual homographs (English version measuring interference from L1 to L2, and Polish version measuring interference from L2 to L1), LexTALE (Lemhofer & Broersma, 2012) in L1 and L2 to measure passive proficiency in both languages, picture naming and verbal fluency tasks to measure production abilities and language background questionnaires.
Both groups demonstrated comparable L1 and L2 general proficiency, but differed in lexical access in production: the immersed-group performed similarly in both languages, whereas non-immersed scored higher in L1 than L2. This suggests that the balanced lexical access in the immersed group is likely attributable to the immersion experience rather than general language proficiency. Additionally, the immersed bilinguals outperformed the non-immersed in L2 and underperformed in L1 in language production tasks.
In the interference tasks, the immersed-group showed similar strength of interference in both directions, whereas the non-immersed experienced much stronger L1->L2 than L2->L1 interference. We also observed stronger L2->L1 and weaker L1->L2 interference in the immersed-group than in the non-immersed one. Overall, L2-immersion seems to lead to the balanced activation across languages but limited L1 access.