There are some OCS manuscripts important for their obvious local characteristics. Among these are the following:
(i) The Ostromir Gospel, from the 11th cent. This is a Cyrillic manuscript of 294 folia containing an evangelistary. The source was presumably East Bulgarian, but the scribe's native Russian shows through in the treatment of certain sounds: o^ > u; tru't > tu'rt; tlu't > tu'lt; tri't > ti'rt; 3rd. sg. and pl. pres. ending in -ti'.
(ii) The Prague Fragments, from the 11th cent. The two folia contain translations of liturgical material copied in the Clagolitic script. The linguistic traits are evidently Czech: CS tj, dj > ts, z; vi'shje'khu' with -sh- for OCS vi'sje'khu'; retention of dl; gen. sg. of ja-stems in -je'.
(iii) The Freising Texts, from the late 10th to early 11th cents. These are three texts found in a Latin codex; the orthography is based on that of Old High German. The texts are a confessional formula, a homily, and a prayer. The language is believed to be somewhere between Slovene and OCS, but has not been precisely characterized.
The following is an excerpt from the Life of Constantine (Cyril). It relates the story of the original request from the Moravian prince to the Byzantine emperor for a priest who could teach the Christian doctrine in their native language. Of course the emperor chose Constantine, and thus began the chain of events which led to the object of study in these lessons.
The following passage has several features which should be pointed out. First there are some simple orthographic conventions: o is often written for o; sht is typical for sht; u may be written for u; th is written for f. Second, there are important phonological shifts represented in the orthography. In particular, in the dialect of the author or scribe, o^ was denasalized to u. Thus one finds the first person singular present form mogu instead of the expected mogo^. Similarly there is loss of the nasal quality of e^, so that e^ and a merge. This leads to forms such as utchitele^ for the usual genitive singular utchitel'ja, as well as jazyku' for the usual je^zyku'. The third person singular and plural of the present tense also shows the ending -ti' rather than -tu', e.g. imuti' for usual imo^tu', mozheti' for usual mozhetu'.
Vesele^shtu zhe se^ o bodzje' filosothu, paky drugaa rje'tchi' prispje' i trudu' ne mnei pru'vykhu' |
Rostislavu' bo, Moravi'skyi kne^zi', bogomu' ustimu', su'vje'tu' su'tvori su' kne^zi svoimi i s Moravle^ny, posla ku' tsarju Mikhailu, glagole^, ljudemu' nashimu' pogani'stva se^ otvru'gshimu', i po khristianesku' se^ zakonu' dru'zhashtimu', utchitele^ ne imamu' takovago, izhe by ny vu' svoi jazyku' istuju vje'ru khristiani'skuju skazalu', da bysha i iny strany togo zre^shte podobilise^ namu' |
To posli namu', vladyko, episkopa i utchitele^ takovago |
Otu' vasu' bo na vse^ strany vu'segda dobryi zakonu' iskhoditi' |
Su'bravu' zhe tsari' su'boru', prizva Koni'stantina filosotha, i su'tvori i slyshati rje'tchi' siju i retche, filosothe, vje'mi' te^ trudna sushta, no dostoiti' tebje' tamo iti |
Sia bo rje'tchi ne mozheti' inu' niktozhe ispraviti, jakozhe ty |
Otvje'shta filosothu', i trudenu' sy tje'lomu' i bolenu', radu' idu tamo, ashte imuti' bukvi vu' jazyku' svoi |
I retche tsari' ku' nemu, dje'du' moi, i oti'tsu' moi, i inii mnodzi, iskavshe togo ne obrje'li suti' |
To kako azu' mogu obrje'sti |
Filosothu' zhe retche, to kto mozheti' na vodje' besje'du napisati |
ili eretitchi'sko ime^ sebje' obrje'sti |
Otvje'shta emu paky tsari' su' Vardoju, uemu' svomu', ashte ty khoshteshi, to mozheti' bogu' tebje' dati, izhe daeti' vsje'mu', izhe prose^ti' nesumnje'niemu', i otvru'dzaeti' tlu'kushtimu' |
Shedu' zhe filosothu', po pru'vomu obytchaju, na molitvu se^ nalozhi i su' inje'mi su'pospje'shniky |
Vu'skorje' zhe se emu bogu' javi, poslushajai molitvy rabu' svoikhu' |
I togda slozhi pismena i natche^ besje'du pisati evaggeli'skuju,
iskoni bje' slovo i slovo bje' u boga, i bogu' bje' slovo, i protche^ja |
Vesele^shtu zhe se^ o bodzje' filosothu, paky drugaa rje'tchi' prispje' i trudu' ne mnei pru'vykhu' | Rostislavu' bo, Moravi'skyi kne^zi', bogomu' ustimu', su'vje'tu' su'tvori su' kne^zi svoimi i s Moravle^ny, posla ku' tsarju Mikhailu, glagole^, ljudemu' nashimu' pogani'stva se^ otvru'gshimu', i po khristianesku' se^ zakonu' dru'zhashtimu', utchitele^ ne imamu' takovago, izhe by ny vu' svoi jazyku' istuju vje'ru khristiani'skuju skazalu', da bysha i iny strany togo zre^shte podobilise^ namu' | To posli namu', vladyko, episkopa i utchitele^ takovago | Otu' vasu' bo na vse^ strany vu'segda dobryi zakonu' iskhoditi' | Su'bravu' zhe tsari' su'boru', prizva Koni'stantina filosotha, i su'tvori i slyshati rje'tchi' siju i retche, filosothe, vje'mi' te^ trudna sushta, no dostoiti' tebje' tamo iti | Sia bo rje'tchi ne mozheti' inu' niktozhe ispraviti, jakozhe ty | Otvje'shta filosothu', i trudenu' sy tje'lomu' i bolenu', radu' idu tamo, ashte imuti' bukvi vu' jazyku' svoi | I retche tsari' ku' nemu, dje'du' moi, i oti'tsu' moi, i inii mnodzi, iskavshe togo ne obrje'li suti' | To kako azu' mogu obrje'sti | Filosothu' zhe retche, to kto mozheti' na vodje' besje'du napisati | ili eretitchi'sko ime^ sebje' obrje'sti | Otvje'shta emu paky tsari' su' Vardoju, uemu' svomu', ashte ty khoshteshi, to mozheti' bogu' tebje' dati, izhe daeti' vsje'mu', izhe prose^ti' nesumnje'niemu', i otvru'dzaeti' tlu'kushtimu' | Shedu' zhe filosothu', po pru'vomu obytchaju, na molitvu se^ nalozhi i su' inje'mi su'pospje'shniky | Vu'skorje' zhe se emu bogu' javi, poslushajai molitvy rabu' svoikhu' | I togda slozhi pismena i natche^ besje'du pisati evaggeli'skuju, iskoni bje' slovo i slovo bje' u boga, i bogu' bje' slovo, i protche^ja |
(XIV.1) And while the Philosopher was rejoicing in God, another request came, and a task no lesser than the previous. (2) For Rostislav, the Moravian prince, roused by God, took counsel with his princes and with the Moravians, and sent to Tsar Michael, saying: 'Our people, having cast off paganism and conducting themselves according to Christian law, have no such teacher who would explain the true Christian faith to us in our own tongue, so that even the countries here, seeing this, might emulate us. (3) So send us, Master, such a bishop and teacher. (4) For always, into all countries, the good law flows from you.' (5) The Tsar, convening a counsel, summoned Constantine the Philosopher, and bade him hear this request, and said: 'Philosopher, I see that you are weary, and it does not suit you to go there. (6) But there is no one so able to fulfil this request as you.' (7) The Philosopher answered: 'Though tired and feeble in body, I will gladly go there if they have letters for their tongue.' (8) And the Tsar said to him: 'My grandfather, my father, and those many others, though they sought, could not produce this. (9) Then how could I produce it?' (10) But the Philosopher said: 'Then who is able to write speech in water? (11) or to produce for himself the name of a heretic?' (12) The Tsar replied to him, along with Varda, his uncle: 'If you wish it, then God may grant it to you, God who gives to all who ask with confidence and opens the door to those who knock.' (13) And the Philosopher went and, according to the old custom, set himself to prayer with his other companions. (14) And lo God soon appeared to him, heeding the prayers of his servants. (15) And thereupon he created letters and immediately began to write the word of the Evangel: (16) In the beginning was the Word, and the Word was with God, and the Word was God, and so forth.
The infinitive takes the ending -ti, the supine takes -tu'. These are added directly to the verbal root, which undergoes the same phonological changes as a result of either ending.
Stems ending in vowel + glide/sonorant replace the combination with a single vowel:
Root-final velars combine with -t to form the cluster -sht, which then palatalizes a following -u' to -i'. Examples are reko^tu' > reshti, reshti'; mogo^tu' > moshti, moshti'; vri'go^tu' > vrje'shti.
Root-final labials are deleted: tepo^tu' > teti, tetu'; grebo^tu' > greti, gretu'.
The infinitive is a verbal complement often denoting command, desire, ability, or purpose. The subject of the infinitive, if not the same as that of the head verb, is placed in the dative. With jestu' the infinitive may denote possibility or necessity: otu' sego... vidje'ti jestu' silo^ khristosovo^ 'from this... (one ought) to see the power of Christ', 'from this Christ's power is to be seen'; nje'stu' namu' ubiti 'it is not for us to kill', 'we ought not to kill'. Result may be indicated by use of jako with the infinitive: ispli'nishe^ oba korabl'ja jako pogro^zhati se^ ima 'they filled both ships so as for them to sink', 'they filled both ships so that they began to sink'.
The supine is used after verbs of motion to denote purpose, e.g. ido^ rybu' lobiti 'I go for the catching of fish', 'I go to catch fish'; pride vidje'tu' groba 'she came for the seeing of the sepulchre', 'she came to see the sepulchre'. Note the object of the action of the supine is in the genitive. The supine, however, could be replaced in this role of denoting purpose by an infinitive with accusative object.
Certain isolated forms in OCS show the early stages of what becomes a larger trend in later Slavic languages, whereby certain forms of the participial declensions are frozen and function as an invariable gerund. The masculine nominative plural form is frozen in this role: poveli mi drezhe shedu'she pogreti ottsa moego 'suffer me first to go and bury my father', with shedu'she instead of the expected shedu'shu; podoba mi jestu' sje'dje'ti mli'tche^shte 'I like to be seated in silence'; otu' Adama do Moisa rek'she do zakona 'from Adam til Moses, namely to the Law', where rek'she takes the place of the more common si rje'tsi'.
The form se^tu', se^ti is found infrequently and has an unclear origin. It has the meaning 'say', 'says', being equivalent to the aorist retche in its explanatory role: poslushai tchu'to se^tu' evangelistu': slyshavu'she, se^tu', glasu' ido^ vu'spe^tu' i pado^ na zeminitsi 'dear what the Evangelist says: after they heard the voice, he says, they went back and fell upon the earth'.
The fifth conjugation contains the athematic verbs, of which there are only four. There is no suffix between the root and ending, the present tense stem being the same as the verbal root. The verbs are
For those stems ending in the dental -d, the -d becomes -s before t-, and drops before m- or s-.
The verb imje'ti 'to have' has present tense forms according to this conjugation imami', imashi, etc., in addition to forms from the third conjugation imje'jo^, imje'jeshi, etc.
The verbs conjugate as follows.
| Present | jes- | dad- | vje'd- | jad- | ||||
|---|---|---|---|---|---|---|---|---|
| 1st Sg. | jesmi' | dami' | vje'mi' | a'mi' | ||||
| vje'dje' | je'mi' | |||||||
| 2 | jesi | dasi | vje'si | jasi | ||||
| 3 | jestu' | dastu' | vje'stu' | jastu' | ||||
| 1st Du. | jesvje' | davje' | vje'vje' | javje' | ||||
| 2 | jesta | dasta | vje'sta | jasta | ||||
| 3 | jeste | daste | vje'ste | jaste | ||||
| 1st Pl. | jesmu' | damu' | vje'mu' | jamu' | ||||
| 2 | jeste | daste | vje'ste | jaste | ||||
| 3 | so^tu' | dade^tu' | vje'de^tu' | jade^tu' | ||||
| Future | ||||||||
| 1st Sg. | bo^do^ | - | - | - | ||||
| 2 | bo^deshi | - | - | - | ||||
| 3 | bo^detu' | - | - | - | ||||
| 1st Du. | bo^devje' | - | - | - | ||||
| 2 | bo^deta | - | - | - | ||||
| 3 | bo^dete | - | - | - | ||||
| 1st Pl. | bo^demu' | - | - | - | ||||
| 2 | bo^dete | - | - | - | ||||
| 3 | bo^do^tu' | - | - | - | ||||
| Imperative | ||||||||
| 1st Sg. | bo^dje'mi' | - | - | - | ||||
| 2 | bo^di | dazhdi' | vje'zhdi' | jazhdi' | ||||
| 3 | bo^di | dazhdi' | vje'zhdi' | jazhdi' | ||||
| 1st Du. | bo^dje'vje' | dadivje' | vje'divje' | jadivje' | ||||
| 2 | bo^dje'ta | dadita | vje'dita | jadita | ||||
| 3 | bo^dje'te | - | - | - | ||||
| 1st Pl. | bo^dje'mu' | dadimu' | vje'dimu' | jadimu' | ||||
| 2 | bo^dje'te | dadite | vje'dite | jadite | ||||
| 3 | bo^do^ | - | - | - | ||||
| Pres. Act. Part. | ||||||||
| Masc./Neut. N | sy | dady | vje'dy | jady | ||||
| bo^dy | ||||||||
| Fem. N | so^shti | dado^shti | vje'do^shti | jado^shti | ||||
| bo^do^shti | ||||||||
| Pres. Pass. Part. | ||||||||
| Masc. N | - | - | vje'domu' | jadomu' | ||||
| vje'dimu' | ||||||||
| Imperfect | ||||||||
| 1st Sg. | *bje'akhu' | dadje'akhu' | vje'dje'akhu' | jadje'akhu' | ||||
| bje'khu' | ||||||||
| 2 | bje'ashe | dadje'ashe | vje'dje'ashe | jadje'ashe | ||||
| bje' | ||||||||
| 3 | bje'ashe | dadje'ashe | vje'dje'ashe | jadje'ashe | ||||
| bje' | ||||||||
| 1st Du. | *bje'akhovje' | dadje'akhovje' | vje'dje'akhovje' | jadje'akhovje' | ||||
| bje'khovje' | ||||||||
| 2 | bje'asheta | dadje'asheta | vje'dje'asheta | jadje'asheta | ||||
| bje'sta | ||||||||
| 3 | bje'ashete | dadje'ashete | vje'dje'ashete | jadje'ashete | ||||
| bje'ste | ||||||||
| 1st Pl. | *bje'akhomu' | dadje'akhomu' | vje'dje'akhomu' | jadje'akhomu' | ||||
| bje'khomu' | ||||||||
| 2 | bje'ashete | dadje'ashete | vje'dje'ashete | jadje'ashete | ||||
| bje'ste | ||||||||
| 3 | bje'akho^ | dadje'akho^ | vje'dje'akho^ | jadje'akho^ | ||||
| bje'she^ | ||||||||
| Aorist | ||||||||
| 1st Sg. | bykhu' | dakhu' | vje'dje'khu' | jasu' | ||||
| jesu', jakhu' | ||||||||
| 2 | bystu' | dastu' | vje'dje' | jastu' | ||||
| by | da | iz-ja, -je | ||||||
| 3 | bystu' | dastu' | vje'dje' | jastu' | ||||
| by | da | iz-ja, -je | ||||||
| 1st Du. | bykhovje' | dakhovje' | vje'dje'khovje' | jasovje' | ||||
| 2 | bysta | dasta | vje'dje'sta | jasta | ||||
| 3 | byste | daste | vje'dje'ste | jaste | ||||
| 1st Pl. | bykhomu' | dakhomu' | vje'dje'khomu' | jasomu' | ||||
| jakhomu' | ||||||||
| 2 | byste | daste | vje'dje'ste | jaste | ||||
| 3 | byshe^ | dashe^ | vje'dje'she^ | jase^ | ||||
| jashe^ | ||||||||
| Past. Act. Part. | ||||||||
| Masc./Neut. N | byvu' | davu' | vje'dje'vu' | jadu' | ||||
| Fem. N | byvu'shi | davu'shi | vje'dje'vu'shi | jadu'shi | ||||
| Resultative Part. | ||||||||
| Masc. N | bylu' | dalu' | vje'dje'lu' | jalu' | ||||
| Past Pass. Part. | ||||||||
| Masc. N | za-bu'venu' | danu' | -vje'dje'nu' | jadenu' | ||||
| Infinitive | byti | dati | vje'dje'ti | jasti | ||||
| Supine | bytu' | datu' | vje'dje'tu' | jastu' | ||||
| Verbal Noun | byti'je | dani'je | vje'dje'ni'je | jadeni'je | ||||
| za-bu'eni'je |
The participle bo^dy has the meaning 'future', 'yet to come'. Forms such as bje', bje'shte, etc. are classified by some authors as imperfective aorists, rather than imperfects.
Three verbs all pertaining to the concept of 'possession' are worth distinguishing because of the similarity of their roots. These are the following:
These verbs in fact all derive from different treatments of the same basic stem *em- 'take', cf. Latin emo 'I buy'. To the basic root i'm-, which in OCS is pre-jotized to ji'm-, are added the suffixes -je', -a, and zero.
imje'ti, in addition to present forms built according to the third conjugation, displays the following forms:
| Present | Imperative | Imperfect | Aorist | |||||
|---|---|---|---|---|---|---|---|---|
| 1st Sg. | imami' | - | imje'akhu' | imje'khu' | ||||
| 2 | imashi | imje'i | imje'ashe | imje' | ||||
| 3 | imatu' | imje'i | imje'ashe | imje' | ||||
| 1st Du. | imavje' | imje'ivje' | imje'akhovje' | imje'khovje' | ||||
| 2 | imata | imje'ita | imje'asheta | imje'sta | ||||
| 3 | imate | - | imje'ashete | imje'ste | ||||
| 1st Pl. | imamu' | imje'imu' | imje'akhomu' | imje'khomu' | ||||
| 2 | imate | imje'ite | imje'ashete | imje'ste | ||||
| 3 | imo^tu' | - | imje'akho^ | imje'she^ | ||||
| imje'jo^tu' | ||||||||
| Pres. Act. Part. | ||||||||
| Masc./Neut. N | imy | |||||||
| imje'je^ | ||||||||
| Fem. N | imo^shti | |||||||
| imje'jo^shti | ||||||||
| Past Act. Part. | ||||||||
| Masc./Neut. N | imje'vu' | |||||||
| Fem. N | imje'vu'shi | |||||||
| Resultative Part. | ||||||||
| Masc. N | imje'lu' | |||||||
| Infinitive | imje'ti | |||||||
| Verbal Noun | imje'ni'je |
imje'ti 'have' derives from the zero grade ji'm- of the root, recalling that ji' is written i. It is also used as an auxiliary verb to build the future tense.
imati 'have', 'take' is a verb of the third conjugation. The stem of the infinitive is the zero grade ji'm-, which in the present system is stengthened to the full grade jem-. The -j- of the present suffix -je- palatalizes -m- to -ml'-. This verb has imperfective aspect.
je^ti 'take', 'seize' is the perfective counterpart of imati. As with imje'ti, this takes the zero grade ji'm- of the root throughout the present. The infinitive stem, however, is built from the full grade jem-.
The aorist relates events in the past, without coordination to other past events. It is used as the primary means of conveying a sequence of past actions in a narrative, whereby the temporal order of the actions is denoted, but no given action is tied to any other concurrent action. Most aorists have perfective aspect. In those instances where the aorist has imperfective aspect, the past inception of the action is denoted, without specifying its completion.
The aorist bystu' is perfective, typically referring to the sudden appearance of something new. Often this is found in initial postition with the sense 'it happened that...', e.g. bystu' zhe ido^shtemu' po po^ti retche edinu' ku' n'emu 'and it happened that, while they were going along the path, a certain man said to him...'.
The imperfect relates past events, but, in contrast to the aorist, these events are correlated with some other past event. The correlated event may be explicit or implicit in the statement. Rather than denoting merely narrative sequence, as the aorist does, the imperfect instead focuses the narrative on a certain action at a certain time. Most imperfects have imperfective aspect. Perfective imperfects denote a completed action correlated with some other event. Often they denote a repeated action. Take as an example ashte se^ su'lutchaashe ne imje'ti jemu nitchi'sozhe dati jemu, to kotygo^... dadjeashe nishtuumu 'if it happened that he had nothing to give him, he would... give his (own) dress to the poor man.'
As an example of the distinction between imperfect and aorist, note the following: ide su' n'imi' i po n'emi' idje'ashe narodu' mu'nogu' i ygnje'taakho^ i 'He went with him, and after him went a great crowd and they pressed on him'. The aorist specifies an action to which the other imperfects are coordinated.
Tense distinguishes events on the basis of the relative times at which they occur. This is the distinction between, say, the aorist and present tenses in OCS. But one may also consider the nature or quality of an action, e.g. whether it is repeated, completed, on-going, regardless of its time of occurrence. This distinction is termed aspect. Interwoven with the prima facie tense system of OCS was a robust and nuanced aspect system, based primarily on the distinction between perfective (completed) and imperfective (on-going) actions. The relation of incompletive to completive could be any of four broad types: (1) un-prefixed to prefixed; (2) difference in verbal classifier; (3) difference in verbal classifier accompanied by changes in the verbal root; (4) suppletion of completely different roots.
The most common perfective-imperfective system arises from stems root+i- (Perfective) contrasted with (vowel-shifted) root+i+aj- (Imperfective). Not all root-vowels change: in this system o changes to a, e to je'. The combination -ia- may trigger jotization in the root final consonant or consonant cluster. There are non-prefixed examples, such as av-i- (P) vs. avlj-aj- (I) 'manifest', vrje'd-i- (P) vs. vrje'zhd-aj- (I) 'anticipate', prost-i- (P) vs. prasht-aj- (I) 'forgive', as well as prefixed examples, such as na-poj-i- (P) vs. na-paj-aj- (I) 'give drink to', u-krje'p-i- (P) vs. u-krje'plj-aj- (I) 'strengthen', u-mri'tv-i- (P) vs. u-mri'shtvlj-aj- 'mortify', pri-gvozd-i- (P) vs. pri-gvazhd-aj- (I) 'nail to'.
The above distinction, however, is not absolute. Some of the i-classifier verbs are themselves imperfective. In general one can only say that aj-classifier verbs are almost exclusively imperfective, while unprefixed i-classifier verbs may be of either aspect. Examples where both the i- and aj-classifier verbs are imperfective are klon-i- (I) vs. klanj-aj- (I) 'bow' and tvor-i- (I) vs. tvarj-aj- (I) 'make'.
Another mode of forming imperfective verbs from perfective ones is by replacing the verbal classfier with +aj-. This may be accompanied by a change of root-vowel, whereby a, je', i, y respectively replace o, e, i', u'; as well as accompanied by Second Palatalization of root-final velars. The perfective root may have zero-classifier, e.g. po-je'd-zero- (P) vs. po-je'd-aj- (I) 'eat' and u-mi'r-zero- (P) vs. u-mir-aj- (I) 'die'; or the root may have a no^-classfier, e.g. u-top-no^- (P) vs. u-tap-aj- (I) 'sink' or vu'z-du'kh-no^- (P) vs. vu'z-dykh-aj- (I) 'sigh'. The perfective may have the a-classfier, e.g. ob-lobu'z-a- (P) vs. ob-lobyz-aj- (I) 'kiss', or je'-classifier, as in po-mi'n-je'- vs. po-min-aj- 'remember'.
There are instances where a perfective root has root-final -j, in which -j is replaced by -v before adding -aj. In certain instances, the -j is treated as a root-final consonant with zero-classifier, and so is modified in the manner discussed above where the classfier is replaced. Sometimes a single root follows both formations. Thus one finds u-bi'j-zero- (P) compares with both u-bij-aj- (I) and u-bivaj- 'beat', 'kill'; similarly po-vi'j- (P) yields both po-vij-aj- (I) and po-vivaj- 'wrap'. A newer formation adds -aj to existing -aj or -je'j, replacing the first -j with -v. This results in -avaj and -je'vaj. Examples are o-del-je'j- or o-dol-je'j- vs. o-del-je'vaj- and o-dol-je'vaj- 'win', 'be victorious', and u-spje'j- vs. u-spje'vaj- 'be of use'. These forms have apparently no change in meaning.
The other major aspect system is non-prefixed imperfective vs. prefixed perfective. An example is tvoriti (I) vs. su'-tvoriti (P) 'do'. Prefixation indicates perfective aspect, except in situations where it is attached to an imperfective verb with the aj-classfier. But a prefix has a meaning of its own and therefore shifts the meaning of the verb to which it is attached, e.g. prje'-tvoriti, although perfective, means 'transform' and not simply 'make'. For each verb, however, there is typically an 'empty prefix' which serves merely to perfectivize, with no attendant lexical change: u-slyshati 'hear', vu's-plakati 'weep'.
In some instances, these morphological changes do not take place. Rather aspect is distinguished by the use of completely different roots. There are a few examples of this, the most notable being reshti (P) vs. glagolati (I) 'say'.
Additional aspect variations may be distinguished. Repeated durative actions with no distinct terminus may be called indeterminate and contrasted with imperfective events which are determinate, having a definite end. As an example, voditu' has the meaning 'he leads (in general)', 'he is a leader' and is indeterminate; this contrasts with vedetu' 'he leads (in a certain direction)'. Indeterminate, or iterative, verbs made up only a small class of verbs related to motion. Many iteratives lost the connotation of repetitive action and gradually shifted to a simply imperfective aspect; at the same time, the imperfect tense took over the role of denoting repetitive actions. Indeterminate aspect in generally characterized by change in the root vowel: ved- 'lead' vs. vod-i- 'lead habitually', nes- 'carry' vs. nos-i- 'carry habitually'.
An important function of the distinction between perfective and imperfective is in the expression of future time. Perfective verbs were used in the present tense to denote a future action; by contrast, imperfective verbs could not express the future but only the present.
It must be borne in mind that the methods for determining the aspect of certain verbs is by no means cut-and-dried. There are few iron-clad formal aspect markers, and generally determination relies on context and on the occurrence of different forms of the same verbal root. In many passages different readings may lend support to different aspect judgements. Even for native speakers of Slavic languages there can arise disagreement on the aspect of given OCS verb forms.