Effects of dominance on language switching: a longitudinal study of Turkish–Dutch children with and without developmental language disorder

Bilinguals frequently switch between languages. The present study examined cued language switching (CLS) longitudinally in bilingual Turkish–Dutch children with (n = 11) and without (n = 30) developmental language disorder (DLD) in a three-wave design with one-year intervals. We studied effects of dominance, indexed by language proficiency and exposure, on overall switching performance and the costs associated with switching between languages. Results show limited evidence for overall costs associated with language switching (i.e., only mixing costs in reaction times [RTs]). Further, accuracy on CLS increased with increasing dominance in the trial language. Moreover, better performance, and larger switching costs, were found in the majority (Dutch) compared to the minority (Turkish) language. These results are discussed in light of the sociolinguistic context. As hypothesized, more errors, longer RTs and slightly larger mixing costs were observed in children with DLD, suggesting overall word retrieval difficulties and difficulties with cognitive control.