Modus
In the grammar of many languages there is a concept of grammatical mood, which describes the relation of the verb to reality or intent in speaking. Many languages express distinctions of mood by changing (inflecting) the form of the verb. Because modern English does not have all of the moods described below and has a very simplified system of verb inflection as well, it is not straightforward to explain the moods in this language. Note too that the exact sense of each mood differs from language to language.
Grammatical mood should not be confused with grammatical tense or grammatical aspect, although these concepts sometimes overlap.
Possible moods include conditional, imperative, indicative, injunctive, negative, optative, potential, subjunctive, and more. 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 Ancient Greek, and Sanskrit retain them all. Some Uralic subjunctive mood has several uses in independent 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 appears to be falling out of common use; many native English speakers do not use it. Example: "I suggested that Paul read books". Paul is not in fact reading the book. Contrast this with the sentence "Paul reads books", where the verb read has the third person singular ending. A more common way of expressing this in current usage might be "I suggested that Paul should read books.", derived more straightforwardly from "Paul should read books." 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 definitely become archaic.
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.
Conditional mood
The conditional mood is used to express uncertainty, particularly (but not exclusively) in conditional clauses. In the phrase "If I were king, you would be queen", "were" is subjunctive while "would be" is conditional. The conditional mood is sometimes considered a tense rather than a mood.
Negative mood
The negative mood expresses a negated action. In most languages, this is not distinct mood; negativity is expressed by adding a particle before (as in Russian or Esperanto: "Li ne iras."), after (as in archaic or dialectic English: "Thou remembrest not?"), or both (as in Afrikaans or French: "Je ne sais pas.".) Standard English brings in a helper verb, to do usually, and then adds not after it: "I did not go there".
In Indo-European languages, it is not customary to speak of a negative mood, since in these languages negation is originally a grammatical particle that can be applied to a verb in any of these moods. In some non-Indo-European languages, the negative mood counts as a separate mood. It could be argued that Modern English has joined the ranks of these languages, since negation in the indicative mood requires the use of an auxiliary verb and a distinct syntax in most cases. Contrast, for instance, "He sings" -> "He doesn't sing" (where the auxiliary to do has to be supplied, inflected to does, and the clitic form of not suffixed to derive the negative from "He sings") with "Il chante" -> "Il ne chante pas"; French adds the (discontinuous) negative particle ne...pas, without changing the form of the verb.
Optative mood
The optative mood expresses hopes or wishes and has other uses that may overlap with the subjunctive mood. Few languages have an optative as a distinct mood; Ancient Greek, Sanskrit and Finnish are three that do. Example: an ancient Greek might say "Would that Paul would read more!" with the words would that expressed by the placing the verb read in the optative mood.
Cohortative mood
The cohortative mood is used to express plea, insistence, imploring, self-encouragement, wish, desire, intent, desire, command, purpose or consequence. It does not exist in English, but phrases such as "let us" are often used to denote it.
Potential mood
The potential mood is a mood of probability, indicating that the action most likely, but not certainly, occurs. It is used in Finnish and Japanese. (In Japanese it is often called something like tentative, since potential is used to refer to a voice indicating capability to perform the action.)
Eventive mood
The eventive mood is used in the Finnish epic poem, Kalevala. It is a combination of the potential and the conditional. It is also used in dialects of Estonian.
In Finnish, there are theoretically forms like this:
- 'kävelleisin' = 'I probably would walk'
Dubitative Mood
The dubitative mood is used in Ojibwa, Turkish and other languages. It expresses the speaker's doubt or uncertainty about the event denoted by the verb.
Hypothetical Mood
The hypothetical mood, found in Russian, Lakota, and other languages, expresses a counterfactual but possible event or situation.
