Directive modality is a deontic modality that connotes the speaker’s degree of requirement of conformity to the proposition expressed by an utterance.
If the usage of the term directive modality is extended beyond discussion of solely grammaticalized means of expression, it becomes nearly synonymous with directive illocutionary point.
(English)
The imperative mood in Stop!
The modal auxiliary verbs may or can in You may/can go at four o’clock
Quirk, Randolph, S. Greenbaum, G. Leech, and J. Svartvik. 1985.A comprehensive grammar of the English language. London: Longman.
Palmer, F. R. 1986.Mood and modality. Cambridge, England: Cambridge University.
Crystal, David. 1980.A first dictionary of linguistics and phonetics. Boulder, CO: Westview.