Language through a prism: Patterns of L2 internalisation and use in acculturated bilinguals

•Acculturation linked to the extent of L2 use in language functions.•Social network profile linked to the extent of L2 use in language functions.•L2 used more frequently in communicative function than in cognitive function.•L2 used more frequently in cognitive function than in inner speech.•Sociocultural integration linked to increased L2 internalisation in bilinguals.

This paper investigates the extent of L2 use in language functions in sequential bilinguals following migration, and reports on patterns of L2 internalisation. Respondents consist of 149 highly educated L2-competent Polish-English bilinguals who relocated to the UK1 as young adults, and underwent processes of acculturation. Language functions under investigation include inner speech, cognitive, and communicative functions. The independent variables include acculturation level, social network profile, length of residence, and predicted future domicile. The study employed both quantitative and qualitative research methods. Respondents completed an online questionnaire and were interviewed by the researcher. The study included the Complementarity Principle into the operationalisation and measurement of language use in bilinguals (Grosjean, 2016). The findings revealed a consistent variation in the extent of L2 use across different language functions. Links were established between the extent of L2 internalisation and acculturation level, social network profile, and predicted future domicile. The results showed that sociocultural integration is a reliable predictor of the extent of L2 use across language functions. This study adds an acculturation perspective to current research on L2 internalisation and language development across lifespan, by measuring and juxtaposing the extent of L2 use across different language functions in sequential bilinguals following migration.