The grammaticalization of gestures in sign languages

Recent studies on grammaticalization in sign languages have shown that, for the most part, the grammaticalization paths identified in sign languages parallel those previously described for spoken languages. Hence, the general principles of grammaticalization do not depend on the modality of language production and perception. However, in addition to these modality-independent paths, some modality-specific paths have been described. Of special interest in this context is the grammaticalization of gestures. Since sign language and co-speech gesture share the visual-gestural modality, sign languages, unlike spoken languages, have the potential to integrate manual and non-manual gestures into their linguistic system. Co-speech gestures cannot only be integrated as lexical items (lexicalization of gestures), but more importantly also as grammatical markers (grammaticalization of gestures). This chapter focuses on the latter type of change, and presents two case studies which illustrate the grammaticalization of manual and non-manual gestures in sign languages.