Modality is the expression of the speaker/writer's beliefs, attitudes etc regarding the proposition being expressed.
There are various types of modality, and different writers categorise them differently and use different terms. However, the most important types are probably :
- Deontic modality expresses attempt to "influence" an event or action - eg : by prohibiting it or insisting on it : You're not allowed to do that! / You must be here by ten
- Epistemic modality indicates the speaker's belief in the likelihood that the event will happen - eg : that it's a possibility, probability or certainty : He might arrive in time; He's liable to be late.
- Dynamic modality, unlike the two types above, is not concerned with the speaker/writer's subjective viewpoint but states the obligation, likelihood etc as a fact. Eg: I can play chess; I'll be 34 next Wednesday; You can smoke in here.
In English, modality may be expressed grammatically and lexically in a variety of ways - through verbs, adjectives, adverbs, nouns etc. Compare :
- I might well see him there.
- I'm likely to see him there.
- There's a good chance of seeing him there
- etc
