Grammatical tense

In grammar, tense is a category that expresses time reference with reference to the moment of speaking.Tenses are usually manifested by the use of specific forms of verbs, particularly in their conjugation patterns.

Basic tenses found in many languages include the past, present, and future. Some languages have only two distinct tenses, such as past and nonpast, or future and nonfuture. There are also tenseless languages, like Chinese, which is traditionally thought to have no tense at all, although recent research suggests that it may possess a future and nonfuture system, which is typical of Sino-Tibetan languages.On the other hand, some languages make finer tense distinctions, such as remote vs. recent past, or near vs. remote future.

Tenses generally express time relative to the moment of speaking. In some contexts, however, their meaning may be relativized to a point in the past or future which is established in the discourse (the moment being spoken about). This is called relative (as opposed to absolute) tense. Some languages have different verb forms or constructions which manifest relative tense, such as pluperfect ("past-in-the-past") and "future-in-the-past".

Expressions of tense are often closely connected with expressions of the category of aspect; sometimes what are traditionally called tenses (in languages such as Latin) may in modern analysis be regarded as combinations of tense with aspect. Verbs are also often conjugated for mood, and since in many cases the three categories are not manifested separately, some languages may be described in terms of a combined tense–aspect–mood (TAM) system.

Uses of the term

In modern linguistic theory, tense is understood as a category that expresses (grammaticalizes) time reference; namely one which, using grammatical means, places a state or action in time.Nonetheless, in many descriptions of languages, particularly in traditional European grammar, the term "tense" is applied to series of verb forms or constructions that express not merely position in time, but also additional properties of the state or action – particularly aspectual or modal properties.

The category of aspect expresses how a state or action relates to time – whether it is seen as a complete event, an ongoing or repeated situation, etc. Many languages make a distinction between perfective aspect (denoting complete events) and imperfective aspect (denoting ongoing or repeated situations); some also have other aspects, such as a perfect aspect, denoting a state following a prior event. Some of the traditional "tenses" express time reference together with aspectual information. In Latin and French, for example, the imperfect denotes past time in combination with imperfective aspect, while other verb forms (the Latin perfect, and the French passé composé or passé simple) are used for past time reference with perfective aspect.

The category of mood is used to express modality, which includes such properties as uncertainty, evidentiality, and obligation. Commonly encountered moods include the indicative, subjunctive, and conditional. Mood can be bound up with tense, aspect, or both, in particular verb forms. Hence certain languages are sometimes analysed as having a single tense–aspect–mood (TAM) system, without separate manifestation of the three categories.

The term tense, then, particularly in less formal contexts, is sometimes used to denote any combination of tense proper, aspect, and mood. As regards English, there are many verb forms and constructions which combine time reference with continuous and/or perfect aspect, and with indicative, subjunctive or conditional mood. Particularly in some English language teaching materials, some or all of these forms can be referred to simply as tenses (see below).

Particular tense forms need not always carry their basic time-referential meaning in every case. A present tense form may sometimes refer to the past (as in the historical present), a past tense form may sometimes refer to the non-past (as in some English conditional sentences), and so on.