Bilinguals activate words from both languages when listening, reading or speaking in one language. Such cross-language activation is considered a hallmark of bilingual language processing. To obtain insight into the impact of biological and linguistic constraints on bilingual processing, the current project compared cross-language activation in bilinguals of two spoken languages (unimodal bilinguals) and deaf and hearing bilinguals of a spoken language and a sign language (bimodal bilinguals). Specifically, we investigated how cross-language activation is shaped by articulatory and perceptual competition between the two languages, and whether deaf readers show similar cross-language activation patterns as hearing signers (and bilinguals of spoken languages). This project contributes critical insight into bilingual processing of deaf language users. Although bilingual schooling for hearing children is nowadays widely accepted in many societies, the benefits of bilingual education programs that teach sign language as well as spoken/written language to deaf children are widely debated and these programs face strong pressure from rapid advances in audiological technology, such as cochlear implants.
We conducted a series of cross-language activation experiments in language production and comprehension with deaf and hearing bilinguals of Spanish Sign Language (LSE) and Spanish, and hearing bilinguals of Basque and Spanish. For example, LSE-Spanish bilinguals had to name pictures in LSE while ignoring a superimposed Spanish word that, when translated into LSE, resembled the LSE sign they had to produce (see Figure 1) to see if this facilitated or slowed down their sign production. In another experiment, we presented a printed Spanish word on the screen together with four objects. The LSE sign for one of the objects on the screen resembled the LSE sign for the Spanish word (see Figure 2) and we measured how often LSE-Spanish bilinguals looked at this object compared to other objects. In another eye-tracking experiment, we presented hearing LSE-Spanish bilinguals with a video of someone speaking and signing at the same time together with the four objects on the screen to investigate how bimodal bilinguals integrate information in the two languages when perceived together (see Figure 3).
The results from this project show that lexical activation flows freely between spoken and signed languages in language production, presumably because the two languages are not competing for the same articulators. Furthermore, the simultaneous perception of words and signs benefits word recognition by hearing bimodal bilinguals. This latter finding challenges the idea that the simultaneous exposure to speech and (natural) lexical signs for deaf children should be avoided. Finally, we show several striking similarities between cross-language activation in deaf and hearing bimodal bilinguals, demonstrating that signing deaf readers are bilingual language users, which needs to be considered when studying their language acquisition and processing.
