Tense is the grammatical category that indicates time, generally indicating a point in time with reference to the moment of the speech act. Tense categories are often presented in the familiar three-way division of past, present, and future, though subdivisions of the past and present are also made in some languages.
These categories say nothing about the state, event or action itself other than to locate it with respect to the moment in which the speaker is in fact speaking. As such, they are more precisely referred to as Absolute Tense.
Absolute Past Tense means that something has been or has occurred prior to right now (e.g. it rained). Absolute Present Tense indicates that something is in effect or is happening right now (e.g. it rains, it is raining). Absolute Future Tense indicates that something will happen at some point subsequent to right now (e.g. it will rain). The examples from the previous sentences illustrate that English generally marks the past tense with the suffix -ed (e.g. walked), though irregular forms forms also occur (e.g. saw, went, got, etc.). The English present tense is usually unmarked, though the suffix -s combines present tense with third person singular (e.g. rains, runs, etc.). [Although, a quirk of English is that the present tense form tends to be interpreted as habitual aspect (see the following section on Aspect), while the progressive aspect -ing is more commonly used to express something happening at the same time as the speech act (e.g. you are reading right now).] The English future tense is not marked by a suffix at all, but rather with the auxiliary verb will (e.g. it will rain.). These categories in English are thus marked by a combination of a suffix attached to the verb (V), an auxiliary or helping verb preceding the verb, or a combination of auxiliary and suffix together.
In Cree, the same basic absolute tense categories are indicated through the addition of prefixes preceding the verb stem. Present Tense is unmarked (Ø; e.g. mētawēw ‘s/he plays, s/he is playing’). Past Tense is marked by adding the prefix kī- (e.g. kī-mētawēw ‘s/he played’). Future Tense is marked by added a prefix which take one of two forms, ka- or ta- (e.g. nika-mētawān ‘I will play’, ta-mētawēw ‘s/he will play’).
The exact use of ka- versus ta- is somewhat variable across Cree communities, even within Plains Cree. The form ka- is typically found when first (e.g. nika-) or second (kika-) persons are indicated (though kika- is often shortened to just ka-). ka- can also be used with third person forms, but ta- is the form more commonly used with third person reference (e.g. ka-mētawēwak versus ta-mētawēwak, both meaning ‘they will play’).
The use of these tense prefixes in Cree is also somewhat complicated by the Order distinction between Independent and Conjunct. As described thus far, the prefixes mark absolute tense on Independent Order Verbs. When added to Conjunct Order verbs, these some prefixes take slightly or even considerably different functions.
Since Conjunct Verbs tend to be dependent on a previously established or contextual referent point, the tense prefixes are no longer always used to indicate time with respect to the moment of the speech act. Instead, they function to relate the time of the verb to some other established timeline which, in contrast to absolute tense, conveys what is known as relative tense. Instead of the familiar categories of past, present and future (absolute) tense, relative tense is commonly divided into anterior, simultaneous and posterior (relative) tenses. Anterior Tense indicates that something happened prior to some other established timeframe, and this is often the function of the prefix kī- when occurring in Conjunct verbs. Simultaneous Tense indicates that something is happening at the same time as some previously established timeframe. Like Present Tense, Simultaneous Tense can be unmarked in Cree, but it can also be marked by the preverb mēkwā- (or the free particular mēkwāc). Posterior Tense indicates that something will occur subsequent to some other established timeframe. The prefix wī- in Cree can sometimes be interpreted to function in this way, while the absolute tense ka-/ta- prefixes most decidedly do not function to indicate posterior tense. Instead, ka-/ta- indicates the modal category of irrealis, which does share certain notions with the future tense, but is a broader category indicating something unrealized or not yet realized (see Mood and Modality).
The notion of Relative Tense sometimes overlaps with Aspect, since both refer to the timeline but not with respect to the moment of the speech act itself. The category of Aspect, discussed in the next section, allows for a greater characterization of the timeframe of the verb. For instance, we have already suggested that the Cree preverb wī- may be a type of (relative, posterior) tense. However, the reference to a time range inherent within the preverb wī- suggests it may be better treated as prospective aspect.