The emergence of complex syntactic structures in Russian Sign Language and Sign Language of the Netherlands

Sign Languages (SLs) are fully-fledged natural languages used by deaf people across the globe. SLs are comparable to spoken languages at all levels. Like in spoken languages, complex sentences involving several clauses develop independently in different SLs. By investigating the development of complex sentences in SLs, we can identify core properties of this process in human languages irrespective of the channel of transmission (i.e., auditory or visual). Previous studies in this field concern primarily very old spoken languages, e.g. Ancient Greek and Latin, and thus remain retrospective because they reconstruct developmental stages, which are not observed in contemporary language data. Most SLs, however, are very young, and therefore provide a unique opportunity to investigate the development of complex sentences as it unfolds and to test hypotheses proposed for older spoken languages. This research investigates the emergence of complex sentences in Russian Sign Language (RSL) and Sign Language of the Netherlands (NGT). First, I conduct a comparative analysis of three constructions in RSL and NGT: coordination of independent clauses, subordination under the noun (i.e., relative clauses) and under the verb (i.e., complement clauses). I collect novel data using various methods including corpus study, elicitation tasks, and grammaticality judgments. Second, I integrate various descriptive and analytic tools previously elaborated for spoken languages to investigate how the observed complex structures emerge in RSL and NGT. The outcomes of this research will add to the typology of complex sentences in SLs and further our understanding of the processes underlying human language development.