Irrealis

In linguistics, irrealis moods (abbreviated IRR) are the main set of grammatical moods that indicate that a certain situation or action is not known to have happened as the speaker is talking. This contrasts with the realis moods.

Every language has a formula for the unreal. Some languages have as many as five levels of "unreality".

The subjunctive mood, sometimes called conjunctive mood, has several uses in dependent clauses. Examples include discussing hypothetical or unlikely events, expressing opinions or emotions, or making polite requests (the exact scope is language-specific). A subjunctive mood exists in English, but it often is not obligatory. Example: "I suggested that Paul eat an apple", Paul is not in fact eating an apple. Contrast this with the sentence "Paul eats an apple", where the verb "to eat" is in the present tense, indicative mood. Another way, especially in British English, of expressing this might be "I suggested that Paul should eat an apple", derived from "Paul should eat an apple."

Other uses of the subjunctive in English, as in "And if he be not able to bring a lamb, then he shall bring for his trespass..." (KJV Leviticus 5:7), have become archaic. Statements such as "I shall ensure that he leave immediately" often sound overly formal, and often have been supplanted by constructions with the indicative, such as "I'll make sure [that] he leaves immediately". (In other situations, the verb form for subjunctive and indicative may be identical: "I'll make sure [that] you leave immediately.)

The subjunctive mood figures prominently in the grammar of the Romance languages, which require this mood for certain types of dependent clauses. This point commonly causes difficulty for English speakers learning these languages.

In certain other languages, the dubitative or the conditional moods may be employed instead of the subjunctive in referring to doubtful or unlikely events (see the main article).

The conditional mood (abbreviated COND) is used to speak of an event whose realization is dependent upon another condition, particularly, but not exclusively, in conditional sentences. In Modern English, it is a periphrastic construction, with the form would + infinitive, e.g., I would buy. In other languages, such as Spanish or French, verbs have a specific conditional inflection. This applies also to some verbs in German, in which the conditional mood is conventionally called Konjunktiv II, differing from Konjunktiv I. Thus, the conditional version of "John eats if he is hungry" is:

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