Editing Grammatical aspect (section)

===Slavic languages===
{{main|Grammatical aspect in Slavic languages}}
The [[Slavic languages]] make a clear distinction between perfective and imperfective aspects; it was in relation to these languages that the modern concept of aspect originally developed.

In Slavic languages, a given verb is, in itself, either perfective or imperfective. Consequently, each language contains many pairs of verbs, corresponding to each other in meaning, except that one expresses perfective aspect and the other imperfective. (This may be considered a form of [[lexical aspect]].) Perfective verbs are commonly formed from imperfective ones by the addition of a prefix, or else the imperfective verb is formed from the perfective one by modification of the stem or ending. [[Suppletion]] also plays a small role. Perfective verbs cannot generally be used with the meaning of a present tense – their present-tense forms in fact have future reference. An example of such a pair of verbs, from [[Polish language|Polish]], is given below:
*Infinitive (and [[dictionary form]]): ''pisać'' ("to write", imperfective); ''napisać'' ("to write", perfective)
*Present/simple future tense: ''pisze'' ("writes"); ''napisze'' ("will write", perfective)
*Compound future tense (imperfective only): ''będzie pisać'' ("will write, will be writing")
*Past tense: ''pisał'' ("was writing, used to write, wrote", imperfective); ''napisał'' ("wrote", perfective)

In at least the East Slavic and West Slavic languages, there is a three-way aspect differentiation for verbs of motion with the determinate imperfective, indeterminate imperfective, and perfective. The two forms of imperfective can be used in all three tenses (past, present, and future), but the perfective can only be used with past and future. The indeterminate imperfective expresses [[habitual aspect]] (or motion in no single direction), while the determinate imperfective expresses [[progressive aspect]]. The difference corresponds closely to that between the English "I (regularly) go to school" and "I am going to school (now)". The three-way difference is given below for the [[Russian grammar#Verbs of motion|Russian basic (unprefixed) verbs of motion]].

When [[prefix]]es are attached to Russian verbs of motion they become more or less normal imperfective/perfective pairs, with the indeterminate imperfective becoming the prefixed imperfective and the determinate imperfective becoming the prefixed perfective. For example, prefix ''при-'' ''pri-'' + indeterminate ''ходи́ть'' ''khodít{{'}}'' = ''приходи́ть'' ''prikhodít{{'}}'' (to arrive (on foot), impf.); and prefix ''при-'' ''pri-'' + determinate ''идти́'' ''idtí'' = ''прийти'' ''prijtí'' (to arrive (on foot), pf.).

 {| class="wikitable"
|-
! colspan="4" | Russian verbs of motion
|-
! colspan="2" | Imperfective 
! rowspan="2" | Perfective
! rowspan="2" | Translation
|-
! Indeterminate !! Determinate
|-
| ходи́ть<br />''khodít{{'}}'' || идти́<br />''idtí'' || пойти́<br />''pojtí'' || to go by foot (walk)
|-
| е́здить<br />''jézdit{{'}}'' || е́хать<br />''jékhat{{'}}'' || пое́хать<br />''pojékhat{{'}}'' || to go by transport (drive, train, bus, etc.)
|-
| бе́гать<br />''bégat{{'}}'' || бежа́ть<br />''bezhát{{'}}'' || побежа́ть<br />''pobezhát{{'}}'' || to run
|-
| броди́ть<br />''brodít{{'}}'' || брести́<br />''brestí'' || побрести́<br />''pobrestí'' || to stroll, to wander
|-
| гоня́ть<br />''gonját{{'}}'' || гнать<br />''gnat{{'}}'' || погна́ть<br />''pognát{{'}}'' || to chase, to drive (cattle, etc.)
|-
| ла́зить<br />''lázit{{'}}'' || лезть<br />''lezt{{'}}'' || поле́зть<br />''polézt{{'}}'' || to climb
|-
| лета́ть<br />''letát{{'}}'' || лете́ть<br />''letét{{'}}'' || полете́ть<br />''poletét{{'}}'' || to fly
|-
| пла́вать<br />''plávat{{'}}'' || плыть<br />''plyt{{'}}'' || поплы́ть<br />''poplýt{{'}}'' || to swim, to sail
|-
| по́лзать<br />''pólzat{{'}}'' || ползти́<br />''polztí'' || поползти́<br />''popolztí'' || to crawl
|-
| вози́ть<br />''vozít{{'}}'' || везти́<br />''veztí'' || повезти́<br />''poveztí'' || to carry (by vehicle)
|-
| носи́ть<br />''nosít{{'}}'' || нести́<br />''nestí'' || понести́<br />''ponestí'' || to carry, to wear
|-
| води́ть<br />''vodít{{'}}'' || вести́<br />''vestí'' || повести́<br />''povestí'' || to lead, to accompany, to drive (a car)
|-
| таска́ть<br />''taskát{{'}}'' || тащи́ть<br />''tashchít{{'}}'' || потащи́ть<br />''potashchít{{'}}'' || to drag, to pull
|-
| ката́ть<br />''katát{{'}}'' || кати́ть<br />''katít{{'}}'' || покати́ть<br />''pokatít{{'}}'' || to roll
|}