Bilingual individuals utilize cognitive control (CC) – monitoring, switching, and suppressing their languages – on a daily basis (Abutalebi & Green, 2007). Language-switching has been extensively studied in the bilingualism literature, including studies that compared language and non-linguistic task switching (e.g., Calabria et al., 2012) and those that used language-switching as a measure of language proficiency (e.g., Vivas et al., 2017).
The aim of this study was to examine the roles of language proficiency and CC in language-switching. This study is ongoing and the following results are based on 23 Thai-English, 4-6 years old children’s performances. The switching task included mixed blocks with a light-switching condition, where the stay-trials were more frequent than the switch-trials, therefore the task required more CC; and a dense-switching condition (more frequent switch-trials), where language-switching was more automatic.
Language proficiency was measured with the Language Experience and Proficiency Questionnaire (LEAP-Q; Marian et al., 2007) and the Cross-linguistic Lexical Tasks (CLT; Haman et al., 2017).
Linear mixed-effects regression analysis revealed a three-way interaction between switching frequency X language X trial type (p<0.01). This result indicated that the switching effect was larger in the light-switching condition that required more CC than in the dense-switching condition, that required less control. Further, the role of language proficiency in language-switching was supported by a moderate correlation between the switch-cost in the light-switching condition for Thai and the Thai CLT scores (rs =0.52,p<0.05), suggesting that children who performed better on the vocabulary task also performed faster on the stay trials during the light-switching condition that resulted in a higher switch-cost. These findings indicate that language-switching involves multiple processes and is highly demanding on both CC and language proficiency.