impact of age of onset on bilinguals’ task switching performance in a nonimmigration context

It is not clear whether bilingualism leads to task switching benefits in single-language nonimmigration contexts, as in dual-language and code-switching immigration contexts. Ninety young Persian-speaking monolingual and bilingual adults reported their language proficiency and use, with the early bilinguals indicating a balanced rating for their L1 and L2, and late bilinguals reporting slightly higher ratings for L1, relative to L2. Concerning the onset age of bilingualism, the bilinguals were classified as early and late bilinguals according to whether they initiated active regular use of the two languages before or after the age of eight. A nonverbal alternating-runs task switching paradigm was used to measure global switch cost (GSC) and local switch cost (LSC). The findings revealed a slight nonsignificant GSC but a significantly lower LSC for early bilinguals, compared to monolinguals, suggesting that bilingualism effects on task switching do not transpire uniformly across different contexts.