[1][2]: 181 [3] That is, it is the use of verbal inflections that allow speakers to express their attitude toward what they are saying (for example, a statement of fact, of desire, of command, etc.).
Some examples of moods are indicative, interrogative, imperative, subjunctive, injunctive, optative, and potential.
Infinitives, gerunds, and participles, which are non-finite forms of the verb, are not considered to be examples of moods.
The original Indo-European inventory of moods consisted of indicative, subjunctive, optative, and imperative.
Not every Indo-European language has all of these moods, but the most conservative ones such as Avestan, Ancient Greek, and Vedic Sanskrit have them all.
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.
For example, in the sentence "If you had done your homework, you wouldn't have failed the class", had done is an irrealis verb form.
Some also preserve an optative mood that describes events that are wished for or hoped for but not factual.
Examples include discussing imaginary or hypothetical events and situations, expressing opinions or emotions, or making polite requests (the exact scope is language-specific).
[citation needed] 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).
In Modern English, this type of modality is expressed via a periphrastic construction, with the form would + infinitive, (for example, I would buy), and thus is a mood only in the broad sense and not in the more common narrow sense of the term "mood" requiring morphological changes in the verb.
The main verb in the protasis (dependent clause) is usually in the subjunctive or in the indicative mood.
However, this is not a universal trait and among others in German (as above), Finnish, and Romanian (even though the last is a Romance language), the conditional mood is used in both the apodosis and the protasis.
Due to English's status as a lingua franca, a common error among second-language speakers is to use "would" in both clauses.
Few languages have an optative as a distinct mood; some that do are Albanian, Ancient Greek, Hungarian, Kazakh, Japanese, Finnish, Nepali, and Sanskrit.
Many languages, including English, use the bare verb stem to form the imperative (such as "go", "run", "do").
The jussive, similarly to the imperative, expresses orders, commands, exhortations, but particularly to a third person not present.
(In Japanese, it is often called something like tentative, since potential is used for referring to a voice indicating capability to perform the action.)
In Finnish, it is mostly a literary device, as it has virtually disappeared from daily spoken language in most dialects.
The presumptive mood is used to express presupposition or hypothesis, regardless of the fact denoted by the verb, as well as other more or less similar attitudes: doubt, curiosity, concern, condition, indifference, and inevitability.
[13][14][15] Note: A few languages use a hypothetical mood, which is used in sentences such as "you could have cut yourself", representing something that might have happened but did not.
Often, there is no doubt as to the veracity of the statement (for example, if it were on the news), but simply the fact that the speaker was not personally present at the event forces them to use this mood.
The second pair implies either that the speaker did not in fact witness it take place, that it occurred in the remote past or that there is considerable doubt as to whether it actually happened.
Mood markers include the past tense hortative (marking encouragement or to urge) aa, the hortative kɞ which denotes a polite tone, min or tin to stress the importance of something, and the word tɞ to denote warning or caution.