语气（mood）或语式是指通过一定的语法形式，说明动作或过程的进行方式，也就是说话者对行为或动作的态度。一般有陈述语气，祈使语气，虚拟语气等。

In linguistics, grammatical mood (also mode) is a grammatical feature of verbs, used for signaling modality. That is, it is the use of verbal inflections that allow speakers to express their attitude toward what they are saying (e.g. a statement of fact, of desire, of command, etc.). The term is also used more broadly to describe the syntactic expression of modality, that is, the use of verb phrases that do not involve inflexion of the verb itself.