Grammatical Mood

In linguistics, grammatical mood is a grammatical (and specifically, morphological) feature of verbs, used to signal modality. That is, it is the use of verbal inflections that allow speakers to express their attitude toward what they are saying (for example, whether it is intended as a statement of fact, of desire, of command, etc.). Less commonly, the term is used more broadly to allow for the syntactic expression of modality — that is, the use of non-inflectional phrases.

Mood is distinct from grammatical tense or grammatical aspect, although the same word patterns are used to express more than one of these meanings at the same time in many languages, including English and most other modern Indo-European languages. (See tense–aspect–mood for a discussion of this.)

Some examples of moods are conditional, imperative, indicative, injunctive, optative, potential, and subjunctive. Infinitive is a category apart from all these finite forms, and so are gerunds and participles. Some Uralic Samoyedic languages have more than ten moods; Nenets has as many as sixteen. The original Indo-European inventory of moods was indicative, subjunctive, optative, and imperative. Not every Indo-European language has each of these moods, but the most conservative ones such as Avestan, Ancient Greek, and Sanskrit have them all. English has the indicative, imperative, and subjunctive moods; others, such as the conditional, do not appear as morphologically distinct forms.

Not all of the moods listed below are clearly conceptually distinct. Individual terminology varies from language to language, and the coverage of (e.g.) the "conditional" mood in one language may largely overlap with that of the "hypothetical" or "potential" mood in another. Even when two different moods exist in the same language, their respective usages may blur, or may be defined by syntactic rather than semantic criteria. For example, the subjunctive and optative moods in Ancient Greek alternate syntactically in many subordinate clauses, depending on the tense of the main verb. The usage of the indicative, subjunctive and jussive moods in Classical Arabic is almost completely controlled by syntactic context; the only possible alternation in the same context is between indicative and jussive following the negative particle lā.