Language-switch costs and dual-response costs in bimodal bilingual language production

In communication, different forms of language combinations are possible for bimodal bilinguals, who use a spoken and a signed language. They can either switch from one language to another (language switching) or produce a word and a sign simultaneously (language blending). The present study examines language control mechanisms in language switching and simultaneous bimodal language production, comparing single-response (German or German Sign Language) and dual-response trials (Blend of the German word and the German Sign Language sign). There were three pure blocks, one for each Target-response (German, German Sign Language, Blend), as well as mixed blocks, in which participants switched between all three Target-responses. We observed language mixing costs, switch costs and dual-response costs. Further, the data pattern showed a specific dual-response advantage for switching into a Blend (i.e., a dual-response trial), indicating the specific nature of a blended response in bimodal bilingual language production.