🗣️ 2. Vowels

Standard Ukrainian has six vowel phonemes: /i/ і, /ɪ/ и, /ɛ/ е, /ɑ/ а, /ɔ/ о, /u/ у. There is no phonemic length, no nasal vowel and no vowel harmony. Unstressed vowels are reduced only a little: е and и approach each other, о moves towards у before a stressed у, and the other vowels keep their quality. This weak reduction, with open syllables and voiced consonants, is what the Ukrainian tradition calls the милозвучність (mylozvučnist') 'euphony' of the language (Bas-Kononenko 2019). This chapter gives the system (§1), the vowels in unstressed syllables (§2), the iotated letters (§3), the distribution of і and и (§4), the vowel alternations of the stem (§5), diphthongs and prothesis (§6–7), vowels in loans (§8), frequencies (§9), and what Mova does (§10).

The descriptions are those of Simovych (1919 §§11–17, 50–57) and Smal-Stockyj (1913 §§2, 4, 8–9), with the rules of the 2019 orthography (Pravopys 2019 §§1–4, 9–10, 129–137). Transliteration and notation are as in 1. Consonants.

1. The system

Four degrees of height, not three, is the modern description; Bas-Kononenko (2019) criticizes the academic orthoepic dictionary (2001–2003) for printing the older three-level table, which in her view casts doubt again on the phonological status of /и/ that N. Tots'ka had established.

1.1 The open vowels

а, е, о are open: а is a clear, central [ɑ] ~ [a] ("the bright Italian a"), е an open [ɛ] "as in German Herr", о an open [ɔ] "as in German Wort" (Smal-Stockyj 1913 §2). Simovych (1919 §14) adds a pedagogical warning: а, е, о and in part и are "open" vowels, to be said without tightening the lips or teeth, or they turn into "foreign (for instance Russian) closed vowels".

1.2 и and і

The pair и / і is the centre of the Ukrainian system and the clearest audible difference from Russian and Polish.

• і /i/ is a high front vowel, as in other languages: ліс (lis) 'forest', кіт (kit) 'cat', ніч (nič) 'night'.
• и /ɪ/ is a high-mid front vowel, slightly retracted: син (syn) 'son', риба (ryba) 'fish', ходити (xodyty) 'to walk'. Smal-Stockyj (1913 §2) describes it as "a closed e, roughly the German e in geht, the French é, but not lengthened"; Simovych (1919 §14) insists that it is made "on the palate, not in the throat like the Russian ы", and that "no other language has this sound; the nearest is the German closed e".

The Ukrainian и is the merger of Common Slavic *i and *y (Simovych 1919 §26 n. 1: ходити, риба beside Russian ходить, рыба); the Ukrainian і comes mostly from old *ě and from *o, *e in closed syllables (§5.1). This is why a dental before и is hard (тин [tɪn] 'fence') and before і soft (тінь [tʲinʲ] 'shadow'): 1. Consonants §3.3.

Minimal pairs: бик (byk) 'bull' ~ бік (bik) 'side'; лис (lys) 'fox' ~ ліс 'forest'; кит (kyt) 'whale' ~ кіт 'cat'; мир (myr) 'peace' ~ мір (gen. pl. of міра 'measure'); дим (dym) 'smoke' ~ дім (dim) 'house'.

2. Unstressed vowels

2.1 е and и

In unstressed syllables е and и lose their distinctness: unstressed е is pronounced close to и ([ɛᶦ]), unstressed и close to е ([ɪᵉ]). The orthoepic dictionaries transcribe them as [еи] and [ие]:

Simovych (1919 §17) uses мене to show pupils that "not every written е means е: in мене the first е differs from the second; it comes near to и". The orthography handles the merger by morphology: an unstressed е or и is written as under stress in a related form (село́ because се́ла, шепоті́ти because ше́піт, трима́ти because стри́мувати, криве́ because кри́во), and where no related form has the stress, by the dictionary (лева́да 'meadow', кише́ня 'pocket', мину́лий 'past'; Pravopys 2019 §1). The spelling therefore keeps a distinction that unstressed pronunciation blurs; spelling errors of the е/и type are the commonest vowel errors of pupils and of writers from Russian-speaking backgrounds, for whom unstressed е sounds like Russian [ɪ].

2.2 о before a stressed у

Unstressed о is pronounced with a shift towards у ([oᵘ]) when the next syllable has a stressed у, і or (less) another high vowel: кожух [koᵘˈʒux] 'sheepskin coat', зозуля [zoᵘˈzulʲɑ] 'cuckoo', голубка [ɦoᵘˈɫubkɑ] 'dove'. In all other positions unstressed о keeps its quality: молоко [mɔɫɔˈkɔ] 'milk', голова [ɦɔɫɔˈʋɑ] 'head', with no trace of the Russian akanye ([məɫɐˈko]). Smal-Stockyj (1913 §2) states the same in general terms: the openness of е and о "diminishes or disappears only in unstressed syllables, e going as far as a closed e, o as far as u". Simovych (1919 §17) notes that in до дому 'home(wards)' the first о "comes near to у". An akanye-like reduction of о to [ɐ] is one of the phonetic marks of Russian-influenced speech and of surzhyk (8. Regional varieties, diaspora and surzhyk).

2.3 а, у, і

Unstressed а, у and і are not reduced: вода [ʋɔˈdɑ] 'water', рука [ruˈkɑ] 'hand', ріка [rʲiˈkɑ] 'river'. Bas-Kononenko (2019) counts weak reduction of unstressed vowels, together with secondary stress in long words, among the two factors that make Ukrainian speech "smooth".

3. The iotated letters я, ю, є, ї

ї always stands for [ji]; it never follows a consonant directly (only after a vowel, an apostrophe or ь: Віньї, Pravopys 2019 §3). The letters йо and ьо write [jɔ] and [ʲɔ] (його 'his', йому, льон 'flax', сьомий; §8). Smal-Stockyj (1913 §4) gives the reading rule in the same terms and notes the special value after р: ря, рю, ре were in his description a hard r followed by a short [i̯] (ряд, трюхом, пір'я), an old feature now replaced by a soft /rʲ/ (1. Consonants §3.2).

Simovych (1919 §16) calls я, є, ї, йо, ю the "soft" vowels and pairs them with а, е, і, о, у; "only и has no soft counterpart". The pairing is orthographic: phonologically the softness belongs to the consonant or is a separate /j/.

4. The distribution of і and и

4.1 In native words

• After a hard consonant: и (сила 'strength', ходити). After a soft dental the letter is і (тіло 'body', сіно 'hay', цілий 'whole'); after labials, hushing consonants, velars and р both occur, and the choice is lexical, by etymology (бик / бік, риба / ріка, шия 'neck' / шість 'six'). Simovych (1919 §51) gives the rule for the *ě reflex: this і "never changes" in inflection (тіло, тіла, тілу) and softens a preceding т, д, с, з, ц, л, н, but not labials and р (вітер, біда, піхота).
• Word-initially the letter is і, as pronounced: Іван, іграшка 'toy', ікона, ім'я 'name', іноді 'sometimes', існувати 'to exist', істина 'truth', іти 'to go' (Pravopys 2019 §2). Initial и is limited to a few interjections and particles (ич!, ич який хитрий), the verb икати 'to say и for і' and its noun икання, some Turkic and Oriental words (ирій beside ірій 'the warm land of migrating birds', ирод beside ірод 'cruel man') and names (Кім Чен Ин) (§2). The variant и- forms are old, native and legitimate: an example of an old form that the 2019 code restored as an equal variant.

4.2 In loans: the "rule of nine"

The 2019 orthography writes и, not і, in common nouns after the nine consonants д, т, з (дз), с, ц, ж (дж), ч, ш, р before another consonant: диплом, директор, інститут, система, цифра, режим, джинси, шифр, фабрика, бригада (§129 III.1). In other positions the foreign [i] is і: at the start of a word (ідея), before a vowel (матеріал, діалектика), at the end (таксі, журі) and after the other consonants (бізнес, пілот, кілограм, хімія); long-established loans keep и after labials and velars (вимпел, кипарис, лиман, миля, спирт) and the Church words of Greek origin keep it as well (диякон, єпископ, митрополит, християнство) (§129 I–III). Personal names have і (Дідро, Дізель), place names follow special lists (Вашингтон but Сідней; Бразилія, Єрусалим, Китай, Сирія by tradition).

Usage diverges from the rule in recent English loans. Hordiienko (2024) lists стрім, стрімінговий, скріншот, сторітелінг as common non-normative spellings of стрим, стримінговий, скриншот, сторителінг. In the Leipzig news sample of 2024 (1 000 000 sentences; counts of 2026-11-06) the norm and the variant stand:

Дизайн, an older loan, follows the rule without exception; the newest loans waver, and скріншот is ahead of the norm by two to one. Such words are where usage is ahead of, or apart from, the code, and where the next edition of the dictionaries will have to choose (6. Spelling rules and the 2019 orthography).

5. Vowel alternations in the stem

5.1 о, е ~ і

The most characteristic Ukrainian alternation: о and е of an open syllable alternate with і in a closed one (Pravopys 2019 §9; Smal-Stockyj 1913 §9):

The alternation also runs through word formation (робітник ~ робота, вільний ~ воля, сільський ~ село, підніжжя ~ нога; §9.1.2). Smal-Stockyj (1913 §9) gives the history: the old o in a syllable closed by the loss of a weak ъ, ь passed through [u] and diphthongs to і; his account and Simovych's (1919 §25) both note that dialects keep the intermediate stages (Simovych: diphthongs in Chernihiv dialects, куінь for кінь, ніус for ніс). 9. Older Ukrainian and the old forms alive today has the history.

Where о, е do not become і in a closed syllable (Pravopys 2019 §9.2):

• when the vowel itself is inserted or fleeting (§5.3): вікно — вікон, казка — казок, день — дня, сон — сну;
• in the groups -ор-, -ер-, -ов- between consonants: торг, смерть, вовк, шовк;
• in the "full-vowel" groups -оро-, -оло-, -ере-, -еле-: мороз, порох, волос, берег, серед, через, зелень (but моріг, поріг);
• in the genitive plural of nouns in -ення: значень, положень;
• in a stem levelled from other forms: борець — борця, носок — носка.

Conversely, і stands in an open syllable where the stem was levelled after the nominative: дзвінок — дзвінка, олівець — олівця, рівень — рівня, кіготь — кігтя (§9.3). Long-established loans have joined the alternation by analogy: Антін — Антона, колір — кольору, папір — паперу, курінь — куреня (§9.2 n.).

5.2 е ~ о after hushing consonants and й

After ж, ч, ш, щ, дж, й the old е stays before a soft consonant and before a syllable with е or и, and becomes о before a hard consonant or a syllable with а, о, у (Pravopys 2019 §10):

5.3 Inserted and fleeting vowels

о and е that appear only in a closed syllable come from the old reduced vowels ъ, ь ("fleeting" vowels): сон — сну 'sleep', день — дня, вітер — вітру 'wind', вогонь — вогню 'fire', травень — травня 'May', кравець — кравця 'tailor'. Smal-Stockyj (1913 §8) explains them as the first of two weak vowels kept where the cluster would otherwise be unpronounceable (сън > сон, кравьць > кравець), "and on such models an o was later really inserted". Insertion is productive in the genitive plural: казка — казок, сосна — сосон, вузол — вузла (the last a fleeting vowel in the nominative). Bas-Kononenko (2019) presents these "inserted vowels" as a euphonic resource: the sonorants л, н, р draw a supporting vowel to themselves.

A few nouns keep the vowel in all forms against the rule: лоб — лоба, мох — моху, рот — рота, лев — лева (§9.2 n. 1).

5.4 о ~ а in verbs

In verb roots о alternates with а to mark iterative or imperfective meaning: допомогти — допомагати 'to help', гонити — ганяти 'to chase', котити — качати 'to roll', кроїти — краяти 'to cut' (Pravopys 2019 §11). The alternation is lexical; 13. Verbs and 16. Derivation: prefixes treat the aspect side.

6. Diphthongs

Standard Ukrainian has no phonemic diphthongs, but a vowel followed by й or by the non-syllabic [u̯] of в forms a falling diphthong in pronunciation: край [krɑj] 'edge', мій 'my', знав [znɑu̯] 'knew', вовк [ʋɔu̯k], Київ [ˈkɪjiu̯]. Smal-Stockyj (1913 §4) describes exactly this: Ukrainian writes the unstressed end of a diphthong "with the sign of the neighbouring consonant" (дай, сей, пий, той, чуй; дав, рев, пив, рів, вовк), although no consonantal noise is heard; Simovych (1919 §15) lists ай, ой, ей, ий, уй and ав, ев, ив, ів, ов. Where the 1913 description has a diphthong іу, уу in бій, був "of short span", the modern norm has [ij], [uu̯].

Dialects have true diphthongs in place of the standard і from о, е (northern, Polissian куонь, віул; Simovych 1919 §25): 8. Regional varieties, diaspora and surzhyk.

7. Prothesis

Ukrainian avoids a word-initial о and у before consonants, and the language has fixed prothetic consonants in a number of native words:

Smal-Stockyj (1913 §9, n.) notes that a prothetic в goes back to the time when initial о in a closed syllable had become у, not yet і, and that вугол for угол 'corner', вугіль for угіль 'coal' were "usual in Ukrainian"; the standard keeps кут 'corner' and вугілля, and the prothesis is now lexical, not productive. Loans do not take it (Україна, ультиматум, Одеса). On the alternation у ~ в at the start of words (учитель / вчитель) see 4. Connected speech §2.

8. Vowels in loans

• [e] is е: енергія, ера, філе; after a vowel, ь or apostrophe, and in a set of Church words, є: конвеєр, реєстр, клієнт, досьє, круп'є; єпископ, Євангеліє (Pravopys 2019 §130.1). After a prefix or first element ending in a vowel, е stays: діелектрик, поетапний, мініескалатор.
• French [y] after ж, ш is у: брошура, журі, парашут (§130.2).
• Doubled vowels are written doubled only in foreign proper names: Аахен, Авраам, Саарбрюкен, Ванзее (§137); common nouns have single vowels (кооперація is a prefix junction, not a doubled vowel).
• English vowels and diphthongs: [æ] is usually а (спам, чат, хакер), by tradition е in some words (бізнесмен, менеджер); [ei] is ей (гейм, дисплей), [ou] оу (шоу, сноуборд), with older adapted forms in е, о (леді, гол, готель) (§§133–134); Hordiienko (2024) documents the wavering of [æ] between а and е (айпад / айпед, геймпад / геймпед) and of [ei] between а and ей (донат 418 against донейт 2 in the news sample of §4.2: usage has settled on донат against the rule of §133, Hordiienko's example).

9. Frequencies

Vowel letters in the first 300 000 sentences of the Leipzig ukr_news_2024 collection (24 172 419 Cyrillic letters and apostrophes, 2026-11-06; for the consonants see 1. Consonants §10):

Vowel letters make up 42.5% of all letters; о is the most frequent letter of Ukrainian text, as in Russian, but и and і together (12.1%) outweigh а. The share of у is inflated, and that of в deflated, by the euphonic alternation of the prepositions у/в (4. Connected speech §2). The figures are of written news; they describe the genre, not the spoken language, and they count letters, not phonemes (я, ю, є, ї write [j] + vowel at the start of words and after vowels).

10. How Mova handles vowels

Mova has no model of Ukrainian vowels. There is no pronunciation, no stress (needed for vowel quality), and no model of the alternations.

• The kg crate sees vowels as letters. morph::norm (kg/src/morph.rs) removes the combining stress marks U+0301 and U+0300 before lookup, so a text with stress marks (dictionaries, textbooks, the 2019 orthography itself) is looked up as plain text; nothing else is normalized.
• Alternations are listed, not derived. кінь — коня, вечеря — вечори, сон — сну are all separate forms in VESUM (dict_corp_vis.txt.bz2, CC BY-NC-SA, research and tests only), and kg analyses and synthesizes them by lookup. A word VESUM lacks has no analysis at all: kg rejects the sentence rather than guess (kg — the Mova knowledge graph). There is no rule that would derive the genitive of an unknown noun with the і ~ о alternation; 11. Nouns has the paradigms.
• The English tree parser reads Ukrainian UD through en xpos-fill; vowels matter only as letters of word forms, and an и/і spelling variant (скриншот / скріншот) is an unknown word unless training has seen it.
• No variant table. The и-initial variants of §4.1 and the і/и variants in loans of §4.2 are not linked.

What would be needed. The vowel rules of §2 are simple given the stress; a Ukrainian grapheme-to-phoneme module (see 1. Consonants §11) would apply them after a stress model (3. Syllable, stress and intonation §8). For lemmatization of unknown words, the alternations of §5 are a closed set of rules that could be coded and tested against VESUM in the research path; for a release path the paradigms would have to come from an open source (Wiktionary is CC BY-SA, learning and tests only).

Sources for this chapter

• Simovych, Vasyl'. 1919. Hramatyka ukrajins'koji movy dlja samonavčannja ta v dopomohu škil'nij nauci. §§11–17, 25–26, 50–57. Public domain. Library books/s/si/simovych-1919-hramatyka-ukrainskoi-movy-dlia (uk-gram-simovych-1919).
• Smal-Stockyj, Stephan. 1913. Ruthenische Grammatik. §§2, 4, 8–9. Public domain. Library books/s/st/stockyj-1913-ruthenische-grammatik (uk-gram-smal-stockyj-1913); archive.org/details/ruthenischegramm00smaluoft
• Ukrajins'kyj pravopys (2019). §§1–4, 8–11, 129–134, 137. Official document, not protected by copyright. Library books/u/uk/ukrainskyi-pravopys-2019 (uk-gram-pravopys-2019).
• Bas-Kononenko, O. V. 2019. Vymovni normy jak mirylo mylozvučnosti ukrajins'koji movy. Ukrajins'ka mova 2019 (1): 103–114. Library card CC BY 4.0; the article prints CC BY-NC-ND 4.0, so paraphrased only (bas-2019-kononenko-orfoepichni-normy); doi.org/10.15407/ukrmova2019.01.103
• Hordiienko, O. Je. 2024. Fonetyko-hrafične osvojennja ta pravopys novitnich zapozyčen'. Ukrajins'ka mova 2024 (4): 97–108. Library card CC BY 4.0; the article prints CC BY-NC-ND 4.0, so paraphrased only (hordiienko-2024-novitni-zapozychennia); doi.org/10.15407/ukrmova2024.04.097
• Counts: Leipzig ukr_news_2024 (1M sentences), CC BY (Goldhahn, Eckart & Quasthoff 2012), leipzig-news-2024; counts of 2026-11-06.
• Mova: kg/src/morph.rs (norm, invisible), kg — the Mova knowledge graph; en/src/main.rs (xpos_fill).

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