Sign bilingualism as a challenge and as a resource

As we set out to conclude the present study on sign bilingualism we are left with an intricate picture of this particular type of bilingualism, still largely unknown to the wider scientific community, that reveals itself as an extraordinary domain of research. Sign bilingualism, as we have learned throughout the preceding chapters, is not only an intricate phenomenon to investigate because it involves languages with different modalities of expression but also because its development and maintenance depends on a complex interaction of internal and external factors.

Toward a cross-disciplinary view of sign bilingualism

With the present work we have sought to contribute to a better understanding of this type of bilingualism that is neither territorial nor commonly the result of par- ent-to-child transmission by adopting a cross-disciplinary perspective. We have elaborated on the main theoretical issues in the domains of bilingualism, education and language acquisition in order to obtain further insights into the factors that shape the development and maintenance of sign bilingualism.

In the first part of the study (chapter 1) we discussed the main hypotheses about bilingualism as a societal phenomenon. We identified the variables that distinguish different types of bilingualism at the societal level, and the types of language planning measures that may be adopted in a given social space. This provided us with the necessary framework to identify the factors that determine the development and maintenance of sign bilingualism at the societal level. We dedicated the remainder of the chapter to education, the key domain of language policy. We examined the main aims of bilingual education and the spectrum of its variation before we turned to bilingual models of education catering for deaf children, focusing first on the developments leading to the implementation of sign bilingual education programmes from a historical perspective before subjecting variation in sign bilingual education to a critical appraisal. The second part of this work concerned the evolution of sign bilingualism from a developmental linguistics perspective (chapters 2-4). We elaborated on the theoretical framework required for the investigation of the bilingual acquisition of a sign language and an oral language in deaf learners (chapter 2) and discussed the main findings obtained in our longitudinal investigation of the acquisition of DGS and German in bilingually educated deaf students (chapters 3 and 4).

All in all, the cross-disciplinary study of sign bilingualism reveals how a complex interaction of sociolinguistic, educational and psycholinguistic factors shapes the linguistic profiles of deaf individuals. In many respects, as becomes apparent throughout the chapters of this work, sign bilingualism represents not only a challenge but also a resource.