Sign bilingualism as a resource
Over the last decades research conducted on language development in diverse acquisition situations, including situations of language contact, has contributed to a better understanding of how inborn language knowledge interacts with the linguistic environment in the learner’s development of the target grammar. While there is a progressive convergence of the different lines of research dedicated to child monolingual, bilingual and adult second language acquisition of hearing learners, studies dedicated to deaf children’s linguistic skills continue to be based for their greater part on the view that language development in this population represents an idiosyncratic phenomenon owing to hearing loss. Hence it comes as no surprise that many myths continue to abound about language acquisition in deaf learners, ranging from the hindering effect attributed to sign language on oral language development to the lack of interaction between two languages considered to be too far apart owing to their difference in the modality of expression.
However, as we believe, circumstances that determine language development in deaf learners, though different in many respects from the (idealised) typical language learner, do not justify its study as an isolated phenomenon. Commonalities and differences between bilingual language acquisition in deaf learners and other types of bilingual language acquisition can only be identified by embedding research on deaf learners into the broader context of developmental linguistics research. The assumption implies that the investigation of deaf learners’ language acquisition, the challenges they face in the course of their development, their errors and their achievements, needs to be footed on a sound theoretical framework that defines the nature of the knowledge attained and the way it is acquired, allowing also for a differentiation of the factors (internal and external) that might affect the developmental process. Only where this requirement is fulfilled will it be possible to determine whether or not sign bilingual deaf learners profit from their bilingualism, using the linguistic resources available to them in a creative manner, as it has been shown to be the case in other types of bilingual language acquisition.