Tense–aspect–mood, commonly abbreviated tam and also called tense–modality–aspect or tma, is the grammatical system in a language that covers the expression of tense (location in time), aspect (fabric of time – a single block of time, continuous flow of time, or repetitive occurrence), and mood or modality (degree of necessity, obligation, probability, ability).[1] In some cases, evidentiality (whether evidence exists for the statement, and if so what kind) may also be included. The term is convenient because it is often difficult to untangle these features of a language. Often any two of tense, aspect, and mood (or all three) may be conveyed by a single grammatical construction; but this system may not be complete in that not all possible combinations may have an available construction. In other cases there may not be clearly delineated categories of tense and mood, or aspect and mood. For instance, many Indo-European languages do not clearly distinguish tense from aspect.[2][3][4][5][6][7][8][9][10] In some languages, such as Spanish and Modern Greek, the imperfective aspect as a whole is fused with the past tense in a form traditionally called the imperfect. This fusion can occur because the imperfective aspect only exists in the past tense. Other languages with distinct past imperfectives include Latin and Persian. Not all languages conflate tense, aspect, and mood, however; close to a theoretically ideal distinction, with separate grammatical markers for tense, aspect, and/or mood, is made in many analytic languages such as Mandarin Chinese and creole languages. Creoles, both Atlantic and non-Atlantic, tend to share a large number of syntactic features, including the avoidance of bound morphemes. Tense, aspect, and mood are usually indicated with separate invariant pre-verbal auxiliaries. Typically the unmarked verb is used for either the timeless habitual or the stative aspect or the past perfective tense–aspect combination. In general creoles tend to put less emphasis on marking tense than on marking aspect. Typically aspectually unmarked stative verbs can be marked with the anterior tense, and non-statives, with or without the anterior marker, can optionally be marked for the progressive, habitual, or completive aspect or for the irrealis mood. In some creoles the anterior can be used to mark the counterfactual. When any of tense, aspect, and modality are specified, they are typically indicated separately with the invariant pre-verbal markers in the sequence anterior relative tense (prior to the time focused on), irrealis mode (conditional or future), non-punctual aspect Hawaiian Creole English (HCE), or Hawaiian Pidgin, is a creole language with most of its vocabulary drawn from its superstrate English, but as with all creoles its grammar is very different from that of its superstrate. HCE verbs[14] have only two morphologically distinct forms: the unmarked form (e.g. teik "take") and the progressive form with the suffix -in appended to the unmarked form (teikin "taking"). The past tense is indicated either by the unmarked form or by the preverbal auxiliary wen (Ai wen see om "I saw him") or bin (especially among older speakers) or haed (especially on Kauai). However, for "to say" the marked past tense has the obligatory irregular form sed "said", and there are optional irregular past tense forms sin or saw = wen si "saw", keim = wen kam "came", and tol = wen tel "told". The past is indicated only once in a sentence since it is a relative tense. The future marker is the preverbal auxiliary gon or goin "am/is/are going to": gon bai "is going to buy". The future of the past tense/aspect uses the future form since the use of the past tense form to mark the time of perspective retains its influence throughout the rest of the sentence: Da gai sed hi gon fiks mi ap "the guy said he [was] gonna fix me up". There are various preverbal modal auxiliaries: kaen "can", laik "want to", gata "have got to", haeftu "have to", baeta "had better", sapostu "am/is/are supposed to". Tense markers are used infrequently before modals: gon kaen kam "is going to be able to come". Waz "was" can indicate past tense before the future marker gon and the modal sapostu: Ai waz gon lift weits "I was gonna lift weights"; Ai waz sapostu go "I was supposed to go". There is a preverbal auxiliary yustu for past tense habitual aspect: yustu tink so "used to think so". The progressive aspect can be marked with the auxiliary ste in place of or in addition to the verbal suffix -in: Wat yu ste it? = Wat yu itin? "What are you eating?"; Wi ste mekin da plaen "We're making the plan". The latter, double-marked, form tends to imply a transitory nature of the action. Without the suffix, ste can alternatively indicate perfective aspect: Ai ste kuk da stu awredi "I cooked the stew already"; this is true, for instance, after a modal: yu sapostu ste mek da rais awredi "You're supposed to have made the rice already". Stat is an auxiliary for inchoative aspect when combined with the verbal suffix -in: gon stat plein "gonna start playing". The auxiliary pau without the verbal suffix indicates completion: pau tich "finish(ed) teaching". Aspect auxiliaries can co-occur with tense markers: gon ste plei "gonna be playing"; wen ste it "was eating".
