🗣️ 14. Irregular verbs, alternations and stress

Ukrainian has few verbs that are irregular in the strict sense. Pravopys 2019 (§115.7) sets apart only four, да́ти 'give', ї́сти 'eat', відпові́сти 'answer' (with the other verbs in -вісти) and бу́ти 'be', with their compounds: they keep the old athematic endings (дам, даси, дасть). Around them is a wider set of verbs whose stems change in ways the two-conjugation rules of 13. Verbs §3 do not predict: іти/йти with its past ішов/йшов, хотіти with хочу, могти with можу, бігти with біжу, взяти with візьму. And every verb, regular or not, has two properties a learner and a parser must look up or compute: the consonant alternations of the present and the passive participle, and the stress pattern, which is free and mobile.

This chapter gives бути (§1), the athematic verbs (§2), іти/йти and its compounds (§3), the other stem-changing verbs (§4), the consonant alternations (§5), stress (§6), and a reference table of the main irregular and alternating verbs with counts (§7); §8 says how Mova handles them.

Counts are from UD Ukrainian 2.18 (IU and ParlaMint, train + dev + test), from VESUM (dict_corp_vis.txt.bz2, release 6.8.6; 47 371 verb infinitive lemmas, reflexives counted separately) and from the Leipzig ukr_news_2024 sample (14.2 million words), all on 2026-11-06. IU and VESUM are non-commercial resources: only counts are given from them. Examples are constructed or taken from the official orthography. Stress is marked with an acute accent where it matters.

1. Бути 'be'

1.1 Forms

Pravopys 2019 §115.7 states that "of the verb бути only the form є is used, which replaces all the other forms (sometimes, in poetic language, єсть for the 1st and 3rd singular); the archaic forms єси for the 2nd singular and суть for the 3rd plural are used rarely". VESUM tags єсть, єси, суть as rare. In the treebanks єсть occurs twice (IU train), єси and суть never. They live in Church and biblical language (Отче наш, що єси на небесах 'Our Father, who art in heaven'), in folk songs and in stylization.

The present є is mostly omitted when it is a copula: Він лікар 'He [is] a doctor', Небо синє 'The sky [is] blue'. It is kept for existence and possession (У мене є брат 'I have a brother', lit. 'at me is brother'), for emphasis, and in definitions and official style (Київ є столицею України 'Kyiv is the capital of Ukraine'), where its use with the instrumental is a calque that handbooks discourage but that is frequent in legal prose (21. Clause structure). Its negative counterpart is немає or нема 'there is not' with the genitive (Немає часу 'There is no time'; 27. Negation).

1.2 Frequency

Бути is by far the most frequent verb: 1 254 tokens in IU, 1 741 in ParlaMint (2026-11-06). As a copula (cop) it occurs 1 324 times across both treebanks, as the auxiliary of the future and the passive (aux) 478 times, as a full verb 509 times at the root of a sentence. The most frequent forms over both treebanks are є (650 including capitalized), було (440), буде (368), будь (443), був (212), бути (206), була (203), були (189), будемо (127), будуть (92). Of the 443 imperatives будь, 442 are in the formula будь ласка 'please' (435 in ParlaMint, where every request for the floor uses it). Будучи occurs 138 times in the Leipzig news sample against 13 of бувши.

The imperative also forms the indefinite prefix будь- (будь-хто 'anyone', будь-який 'any', будь-де 'anywhere'), written with a hyphen (12. Pronouns, determiners and numerals). Compounds of бути (забу́ти 'forget', здобу́ти 'obtain', відбу́тися 'take place', прибу́ти 'arrive'; VESUM has 40 lemmas with a future in -буду) conjugate like бути in the future (забу́ду, забу́деш) but are ordinary perfectives: their "present" is their future, and they have no є.

2. The athematic verbs: дати, їсти, -вісти

These three keep the endings of the old athematic conjugation, without a thematic vowel in the singular (Pravopys 2019 §115.7):

Notes:

• The 2nd singular ends in -си (даси, їси), not in -ш. A 2nd singular дасиш is substandard (VESUM subst) and dialectal.
• The 3rd plural is formed from a stem in -д-: дадуть, їдять, відповідять. The -д- also appears in the imperative of їсти (їж < *ѣдь) and in the imperfective partners: відповіда́ти 'answer' (ipf.), розповіда́ти 'tell'.
• For -вісти verbs Pravopys 2019 §116 Note 1 says that the imperative "usually" comes from the imperfective: доповідай, розповідай. Forms such as розповіж are dialectal or archaic.
• Дати is perfective; its imperfective is давати (даю, даєш, дає: the -ва- is lost in the present, as in вставати — встаю, пізнавати — пізнаю; Pravopys 2019 §115.3 Note).

Compounds. VESUM (2026-11-06) has 57 lemmas whose 1st singular ends in -дам(ся) (видати, віддати, додати, надати, передати, подати, продати, віддатися…), 32 in -їм(ся) (з'їсти, доїсти, наїстися, переїсти, виїсти, в'їстися…) and 15 in -повім (відповісти, розповісти, доповісти, оповісти, переповісти, заповісти, повісти…). All conjugate like the base verb: прода́м, продаси́, прода́сть, продаду́ть. Цвісти 'bloom' and вести 'lead' also end in -вісти/-вести but are regular I-conjugation verbs (цвіту́, цвіте́ш).

In the treebanks (UD 2.18, both treebanks, 2026-11-06): дати 162 tokens (forms дати 45, дали 20, дасть 16, дав 14, дайте 24 with capitalized, дам 7, дамо 6, дано 6, дай 7, дадуть 3, дасте 1, даймо 1); їсти 26 (їсти 10, їв 5, їсть 4, їм 2, їдять 2, їж 2, їстимуть 1); відповісти 23, розповісти 12, доповісти 4.

3. Іти / йти 'go' and its compounds

3.1 The simplex

Іти́ and йти are the same verb; the initial і-/й- alternates by euphony, йти after a vowel and іти after a consonant or a pause in careful style (4. Connected speech §§ on і/й). The present is I conjugation with stressed endings; the past has a different stem, ш-, from an old participle *šьdъ:

In written text the й- forms dominate. UD (2026-11-06): lemma йти 140 tokens against іти 56; forms йде 41 / іде 31. Leipzig news (2026-11-06): йде 2 039 against іде 243, йдуть 937 / ідуть 90, йшов 197 / ішов 31, йшла 232 / ішла 2, йти 1 293 / іти 185. Since most words end in a vowel, euphony itself favours й-; but the ratio (about 8 : 1) is higher than euphony alone would give, so йти is also becoming the unmarked citation form.

3.2 Compounds

Prefixed, the verb becomes perfective, and its shape depends on the prefix:

After consonant-final prefixes an -і- is inserted (від-і-йти, під-і-йти, з-і-йти), and the root keeps -йти. Піти is a contraction and has its own forms (піду, пішов); dialectal пійти exists (VESUM lists it). Знайти 'find' and найти 'come over, find' belong historically to the same root and conjugate the same way (знайду, знайшов). Prefix ви- takes the stress in the perfective (ви́йти, ви́йду, ви́йшов), as with every ви- perfective (§6.4).

VESUM (2026-11-06) has 39 lemmas, reflexives included, whose 1st singular is in -йду / -іду (піду): ввійти, вийти, винайти, відійти, віднайти, дійти, зайти, зійти(ся), знайти, обійти, перейти, підійти, піти, прийти, пройти, розійтися, увійти… In UD the most frequent compounds are піти (114 tokens: піти 24, пішов 20, пішли 21, підемо 14, пішла 9, піду 9, піде 6, …) and прийти (прийшов 13, прийде 8, прийшли 8, …).

The imperfective partners are compounds of ходити: приходити, заходити, виходити, відходити, підходити, обходити; for знайти the partner is знаходити.

4. Other verbs with stem changes

These verbs are regular in their endings but have stems that the class rules do not give. Pravopys 2019 §115.3 lists several of them as "separate verbs" (окремі дієслова).

4.1 Хотіти 'want'

I conjugation with the stem хоч- throughout the present: хо́чу, хо́чеш, хо́че, хо́чемо, хо́чете, хо́чуть; past хоті́в, хоті́ла; imperative хоти́ (rare). The infinitive in -іти would suggest the II conjugation, and the colloquial 3rd plural хотять (VESUM subst; 2 tokens in UD, 0 in the news sample against 2 166 of хочуть) is the analogical II form. The present is frequent: хочу 158 tokens in UD (of 375 tokens of хотіти), largely in ParlaMint's Я хочу сказати… 'I want to say…'. The impersonal reflexive хочеться 'one feels like' has the same stem. Compounds: захотіти, схотіти, перехотіти, розхотіти, відхотіти.

4.2 Могти 'be able'

Stem мог- with г → ж through the whole present: мо́жу, мо́жеш, мо́же, мо́жемо, мо́жете, мо́жуть; past міг, могла́, могло́, могли́ (о → і in the closed syllable); no imperative. Smal-Stockyj (1913 §39) explains можу as levelled from the softened forms: originally *могу had a hard г and можеш a soft one, and "one has got used to using the same consonant before the -у of the 1st person". The 1st singular могу occurs in dialects and as a russianism. VESUM has 21 compounds (змогти, допомогти, перемогти, знемогти, спромогтися, домогтися…), all with -можу. In UD могти has 460 tokens; може 166, можуть 77, можемо 57, міг 41, можу 40.

4.3 Бігти 'run'

II conjugation, but with г → ж in every person, unlike other II verbs where the change is limited to the 1st singular (Pravopys 2019 §115.5 Note): біжу́, біжи́ш, біжи́ть, біжимо́, біжите́, біжа́ть; past біг, бі́гла; imperative біжи́, біжі́м(о), біжі́ть; adverbial participle біжучи́. VESUM has 23 lemmas of the family (вибігти, добігти, забігти, збігтися, перебігти, прибігти, розбігтися, запобігти 'prevent'…). UD: 21 tokens.

4.4 Verbs with nasal and other stem changes

4.5 -ува- and -ва- verbs

Verbs in -ува-/-юва- lose -ва- in the present (будува́ти — буду́ю, малюва́ти — малю́ю) and keep у in the imperative (будуй, малюй). Verbs with the suffix -ва- after a root (бува́ти, відчува́ти) keep it (бува́ю, відчува́ю), but кува́ти — кую́, and the compounds of -давати, -ставати, -знавати lose it (даю, встаю, пізнаю) (Pravopys 2019 §115.3 г and Note). Simovych (1919 §268) notes that older writers (Kvitka) wrote -ова- (силовати) and that this should not be imitated; -ова- survives only where stress falls on it in the passive participle (будо́ваний, мальо́ваний).

5. Consonant alternations in the present

5.1 The rules

II conjugation. In the 1st singular only, and in the passive participle in -ений and the derived imperfectives in -ува-, dental and alveolar stem consonants change (Pravopys 2019 §§15–18, §115.5–6):

Labial stems insert л also in the 3rd plural (лю́блять, ло́влять, ку́плять), in the present adverbial participle (лю́блячи, ро́блячи) and in nouns in -ення (погли́блення) (Pravopys 2019 §18, §115 Note 1). The imperative is built on the 2nd singular stem and has no alternation: ходи, носи, люби.

I conjugation. Where the 1st singular has a change, the whole present has it (Pravopys 2019 §115.4): г → ж (могти́ — мо́жу, мо́жеш), к → ч (пекти́ — печу́, пече́ш; пла́кати — пла́чу, пла́чеш), х → ш (колиха́ти — колишу́, коли́шеш), з → ж (в'яза́ти — в'яжу́, в'я́жеш; каза́ти — кажу́), с → ш (чеса́ти — чешу́; писа́ти — пишу́), т → ч (хоті́ти — хо́чу; шепта́ти — шепчу́), ст → щ (свиста́ти — свищу́), ск → щ (полоска́ти — полощу́). The imperative follows the present: кажи, пиши, плач, колиши.

So плакати — плачу, плачеш (I, change throughout) and платити — плачу, платиш (II, change in the 1st singular only) share the 1st singular плачу 'I cry / I pay', told apart only by stress (пла́чу 'I cry', плачу́ 'I pay') and by the rest of the paradigm.

5.2 How regular are they

The II-conjugation alternations have no exceptions in the dictionary. Counted over VESUM (2026-11-06), for the 7 716 verb lemmas in -ити/-іти that have a 1st singular present or perfective future:

Every non-alternating case is an I-conjugation verb (state verbs in -іти that keep -і-, and monosyllables like бити). The alternation therefore follows from the conjugation class, and the conjugation from the stem (-іти keeping і → I; losing it → II, 13 §3.2). New loans obey the rule at once: апгрейдити — апгрейджу, аутсорсити — аутсоршу, анонсити — аноншу 'announce' (VESUM).

5.3 Other alternations

• Vowel alternation о, е → і in the closed syllable of the masculine past: ніс — несла, віз — везла, міг — могла, ліг — лягла (13 §6.1, Pravopys 2019 §9).
• Vowel alternation in secondary imperfectives: -о- → -а- (допомогти — допомагати), -е-/-о- → -и- (зібрати — збирати, послати — посилати, обтерти — обтирати, замерзнути — замерзати). They are lexical and must be stored.
• Loss of -ну- in the past and infinitive of intransitive -нути verbs (сохнути — сох, 13 §6.1).
• Loss of -ва- in -давати, -ставати, -знавати (§4.5).

6. Stress

Ukrainian stress is free (it can fall on any syllable) and mobile (it can move within a paradigm) (3. Syllable, stress and intonation). In the verb it is distinctive in pairs like пла́чу 'I cry' / плачу́ 'I pay', ві́зьме 'he will take' / never *візьме́, and it is not written in ordinary text. Senyk et al. (2025), building a stress benchmark of 1 026 sentences for speech synthesis, list "stress shifting in inflection" and stress-differentiated homographs among the reasons why Ukrainian stress cannot be read from spelling, and find that even their best combined system puts the stress correctly on 92.5% of words but only on 52.0% of whole sentences.

6.1 Present tense patterns

Three patterns cover most verbs:

In the ending-stressed type of the I conjugation the 1st and 2nd plural stress the final syllable: несемо́, несете́, ідемо́, ідете́, даси́, дамо́, дасте́; in the II conjugation the 1st plural of ending-stressed verbs is біжимо́, лежимо́, мовчимо́.

The mobile pattern is the one that makes stress a property of the lexeme: ходи́ти and ходжу́ would suggest an ending-stressed verb, but хо́диш shows otherwise. Smal-Stockyj (1913 §39) gives lists of -ати verbs with stem stress throughout (бі́гати, ди́хати, ки́дати, слу́хати), with stress on the suffix (чита́ти — чита́ю), and with both possibilities (ду́мати / дума́ти, лапа́ти, сні́дати / сніда́ти), a variation partly still alive.

6.2 Past tense patterns

The past usually keeps the stress of the infinitive (чита́ти — чита́в, чита́ла; бра́ти — бра́в, бра́ла, бра́ло, бра́ли, Pravopys 2019 §115.9). Verbs with a monosyllabic or consonant stem and ending stress in the infinitive move the stress to the endings in the feminine, neuter and plural: нести́ — ніс, несла́, несло́, несли́; могти́ — міг, могла́; бути — був, була́, було́, були́; жи́ти — жив, жила́, жило́, жили́; дати — дав, дала́, дали́.

6.3 Imperative

The imperative ending is stressed when the 1st singular is ending-stressed (пишу́ → пиши́, пиші́ть; ходжу́ → ходи́, ході́ть), and stem-stressed otherwise (ба́чу → бач; ки́ну → кинь). This is why the vowel endings -и, -іть appear exactly where they are stressed (Pravopys 2019 §116.1; 13 §8.1).

6.4 The prefix ви-

The perfectivizing prefix ви- is always stressed in perfectives, in all their forms: ви́писати, ви́пишу, ви́пиши, ви́писав, ви́писаний; ви́йти, ви́йду, ви́йшов; ви́нести, ви́несу. Its imperfectives are not: випи́сувати, вихо́дити, вино́сити. Smal-Stockyj (1913 §38) singles this out as the one exception to "prefixed verbs are conjugated exactly like the simple ones", and Pravopys 2019 §116.1 uses it for the imperative (ви́бери, ви́беріть).

6.5 Variation

Stress varies regionally and between generations, and the dictionaries record doublets. In the verb, frequently cited cases are ду́мати / дума́ти (Smal-Stockyj 1913), сніда́ти / сні́дати 'have breakfast'. No Mova data or count in this manual measures stress; the open stress resources (Ukrainian Word Stress, the Senyk et al. 2025 benchmark) are where a measurement would start.

7. Reference table

The main irregular and alternating verbs, with their token counts in UD 2.18 (lemma, VERB + AUX, IU and ParlaMint) and the number of lemmas in VESUM that share their pattern (the verb and its prefixed compounds, reflexives included; counted on the 1st singular). All counts 2026-11-06.

Families in VESUM count spellings of lemmas, so variant spellings (увійти / ввійти, одповісти / відповісти) count twice; for the alternation rows the number is the size of the whole alternation class in §5.2, not of the verb's own compounds.

8. How Mova handles irregular verbs

• No Ukrainian conjugation in the en crate. The lemmatizer and inflector (en/src/morph.rs) are English. On Ukrainian treebanks the en parser sees forms through tags only (13 §14): дам, даси, дасть get VBP/VBZ like any present; ішов and іти are unrelated strings. Unknown words, which in Ukrainian are mostly unseen inflected forms of known lemmas, make up 23.6% of IU dev tokens; the tagger is 83.74% accurate on them (2026-11-06).
• kg takes irregularity from VESUM. kg/src/morph.rs loads, for every word of the input vocabulary, all its VESUM analyses (pass 1), then all forms of the lemmas found (pass 2), so that a form can be synthesized back from (lemma, grammar) (synth). Irregular paradigms, alternations and the і/й doublets are therefore handled by lookup, not by rule: ішов → іти, візьму → взяти, ляжу → лягти. A verb absent from VESUM is unknown, and kg/src/uk.rs rejects the sentence rather than guess.
• Variants. Where VESUM gives several forms for one grammar (йде / іде, -ться with -ся or -сь), textgen.rs chooses by the frequency of (lemma, grammar) → form in the parsed corpus. No euphony rule chooses йти after a vowel and іти after a consonant.
• Stress. kg::morph::norm deletes U+0301 and other invisible characters before lookup, so stressed input (пла́чу) is accepted, but the stress is lost: пла́чу and плачу́ both map to the same entries. VESUM's corpus file does not carry stress for most forms. Mova has no stress model.
• Not yet: no rule-based conjugator (the tables of §§2–6 are not coded), no stress lexicon, no test set of irregular forms. A conjugator for the regular classes plus a closed list of the verbs in §7, checked against VESUM and the Ukrainian Wiktionary (CC BY-SA, learning and tests only), would remove the dependence on the non-commercial dictionary for the common verbs.

Sources for this chapter

• Український правопис (2019), §§9, 15–18, §115.2–9 (conjugations, athematic verbs, consonant changes, past), §116 (imperative). Official document, not protected by copyright. Library books/u/uk/ukrainskyi-pravopys-2019 (uk-gram-pravopys-2019).
• Smal-Stockyj, Stephan. 1913. Ruthenische Grammatik. Berlin–Leipzig: Göschen. §§38–41 (conjugation classes, stress of -ати verbs, можу). Public domain. Library books/s/st/stockyj-1913-ruthenische-grammatik (uk-gram-smal-stockyj-1913).
• Simovych, Vasyl'. 1919. Граматика української мови. §§259–268 (classes of verbs, -ова-/-ува-). Public domain. Library books/s/si/simovych-1919-hramatyka-ukrainskoi-movy-dlia (uk-gram-simovych-1919).
• Senyk, Anastasiia, Mykhailo Lukianchuk, Valentyna Robeiko & Yurii Paniv. 2025. Context-aware lexical stress prediction and phonemization for Ukrainian TTS systems. UNLP 2025. CC BY 4.0 (senyk-2025-context-aware-lexical-stress-prediction); aclanthology.org/2025.unlp-1.11
• UD Ukrainian IU 2.18 (CC BY-NC-SA 4.0, counts only) and ParlaMint 2.18 (CC BY-SA 4.0).
• VESUM (dict_uk, release 6.8.6), CC BY-NC-SA 4.0: counts only.
• Leipzig Corpora Collection, ukr_news_2024, CC BY: counts.
• Mova: en/src/main.rs, en/src/morph.rs; kg/src/morph.rs (Morph, norm, invisible), kg/src/uk.rs, kg/src/textgen.rs.

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