An ELT Glossary : Modality

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