Topics in sign language linguistics
Crucially, all the questions that have been shown to be relevant in the linguistic investigation of spoken languages can and should also be asked when it comes to the investigation of sign languages. Studies on a broad variety of sign languages are fruitful and interesting for a number of reasons.
Firstly, the field of linguistic typology can benefit from research on sign language typology. A comparison of sign languages to spoken languages (that is, the search for inter-modal variation) will reveal whether established typological concepts and classifications also apply to sign languages. Moreover, linguistic universals must hold across modalities. Otherwise, the status of a proposed universal as a ‘true’ linguistic universal is challenged. The study of inter-modal variation must be complemented by a thorough investigation of intra-modal variation, that is, variation among sign languages. It has, for instance, been hypothesised that sign languages as a group show less structural variation than spoken languages. In order to test this hypothesis it is of utmost importance to study as many genetically unrelated sign languages as possible, ideally from different geographical and social settings.
Secondly, linguistic theories developed on the basis of spoken language data have to be tested against sign language data. Numerous studies to date have shown that existing theories can successfully be applied to sign languages: for instance, Government & Binding Theory and its more recent developments within the Minimalist Program, Head-Driven Phrase Structure Grammar, Optimality Theory, Feature Geometry, Autosegmental Phonology, and Functional Grammar. Of course, sign languages are not only a testing ground for certain theories; theoretical analyses within all frameworks will also lead to a better understanding of sign language structure. Moreover, since sign languages, like spoken languages, are subject to diachronic change, theories of language change have also had to be tested against sign language data.
Thirdly, the analysis of sign languages adds to our understanding of the neurological and psychological basis of language, and of human cognition in general. With respect to neurolinguistics, the study of sign languages (brain-imaging studies and studies of aphasic signers) has shown that the neural systems underlying language are, for the most part, modality-independent. General modality-independence has also been demonstrated for language processing and language acquisition. As with neurolinguistics, modality-specific patterns can be traced back to properties of the respective modality rather than to differing modality-specific design in the language faculty. Hence, modality-specific factors for the most part exert an influence only at the articulatory-perceptual interface.
Fourthly, the study of sign languages is also interesting from a sociolinguistic point of view. Sign languages develop in unusual circumstances. They are usually minority languages and they have no written form. Patterns of language transmission are atypical, since most deaf children have hearing parents, and bilingual development is hindered by the relative inaccessibility of the surrounding spoken language to deaf children. Particularly interesting in this context are situations where new sign languages emerge in educational settings and where sign languages develop in secluded communities with a high incidence of genetic deafness (i.e. village sign languages).
Fifthly, the study of sign language poses particular challenges for the elicitation and documentation of linguistic data. As far as elicitation is concerned, because of the factors outlined above, consultants have to be carefully selected and the elicitation procedure has to be adapted to the specific requirements of the visual-manual modality. When it comes to documentation, absence of a written form for sign languages poses additional problems. To overcome this problem, special notational systems have been developed, and recent documentation systems make use of computer-based annotation of video data.
Topics in sign language linguistics