Assessing the scope of expertise-driven advantages in bimodal and unimodal bilinguals: A comparison of signed and spoken language interpreters

The ‘bilingual advantage hypothesis’ posits that language control during bilingual processing enhances cognitive functioning. However, compared with bilinguals who use two spoken languages (unimodal bilinguals), those who use a signed language and a spoken language (bimodal bilinguals) are shown to not enjoy such an advantage. It is assumed that the different language modalities in bimodal bilinguals allow simultaneous production of two languages and reduce the demands for language control. Comparing bimodal and unimodal interpreters who practice switching between two languages as a profession can provide a window into whether bilingual advantage is modality specific. The participants in this longitudinal study are bimodal professional interpreters, interpreting students, and a control group of non-interpreter bimodal bilinguals. We will compare the results of this study with those of a previous study on spoken language interpreters and interpreting students to see if language modality is a differentiating factor for any observed effects, and if yes, how task demands associated with different modalities are manifested in the impacts on cognitive functions.