Tense, aspect, and modality

Cross-linguistically, the grammatical categories tense, aspect, and modality - when they are overtly expressed - are generally realized by free morphemes (such as adverbials and auxiliaries) or by bound inflectional markers. The discussion in this chapter will make clear that this generalization also holds true for sign languages. It will be shown that tense is generally encoded by time adverbials and only occasionally (and only in a few sign languages) by verbal inflection. In contrast, various aspect types are realized on the lexical verb, in particular, by characteristic movement modulations. Only completive/perfective aspect is commonly realized by free morphemes across sign languages. Finally, deontic and epistemic modality is usually encoded by dedicated modal verbs. In relation to all three grammatical categories, the possibility of (additional) non-manual marking and the issue of grammaticalization will also be addressed