The conditional mood is a grammatical mood used to express a proposition whose validity is dependent on some condition, possibly counterfactual. It thus refers to a distinct verb form that expresses a hypothetical state of affairs, or an uncertain event, that is contingent on another set of circumstances. An example of a verb in the conditional mood is the French aimerait, meaning “would love” (from the verb aimer, “to love”).
Conditional mood often refers to an inflected verb form, like the example just given. However the term is also sometimes used in relation to an analytic construction that performs the same function. Thus a construction like the English would love will sometimes be described as representing the conditional mood. In some informal contexts, such as language teaching, it may be called the “conditional tense”.
The conditional mood is generally found in the independent clause (apodosis) of a conditional sentence, namely the clause that expresses the result of the condition, rather than the dependent clause (protasis) expressing the condition. The protasis will often use a different verb form, depending on the grammatical rules of the language in question, such as a past tense form or the subjunctive mood. This is exemplified by the English sentence “If you loved me you would support me” – here the conditional would support appears in the apodosis, while the protasis (the condition clause) uses instead the simple past form loved.
Not every conditional sentence involves the conditional mood (and some languages do not have a conditional mood at all). For example, in the sentence “If I win, he will be disappointed”, the conditional circumstance is expressed using the future marker will. Also a conditional verb form may have other uses besides expressing conditionality; for example the English would construction may also be used for past habitual action (“When I was young I would happily walk three miles to school every day”), or with future-in-the-past meaning.
Conditional mood can be denoted by the glossing abbreviation COND. Some languages distinguish more than one conditional mood; the East African language Hadza, for example, has a potential conditional expressing possibility, and a veridical conditional expressing certainty.
This article describes the formation of the conditional forms of verbs in certain languages. For fuller details of the construction of conditional sentences, see Conditional sentence (and for English specifically, English conditional sentences).
As is typical for many languages, full conditional sentences in English consist of a condition clause specifying a condition or hypothesis, and a consequence clause or apodosis specifying what follows from that condition. The condition clause is a dependent clause, most commonly headed by the conjunction if, while the consequence is contained in the main clause of the sentence. Either clause may appear first.
Different types of conditional sentences (depending largely on whether they refer to a past, present or future time frame) require the use of particular verb forms (tenses and moods) to express the condition and the consequence. In English language teaching the most common patterns are referred to as first conditional, second conditional and third conditional; there is also a zero conditional and mixed conditional.
Conditionals – zero & first conditionals (English Grammar)