у Львові and в Одесі: Ukrainian’s у/в and і/й

The orthography’s (правопис) example sentences include these two, side by side: Діти побували у Львові (“the children visited Lviv”) and Вона побувала в Одесі (“she visited Odesa”). The preposition meaning “in/at” is у in one and в in the other. The meaning is the same. What differs is the sound that comes before and after.

Ukrainian has several words like this that choose their form based on the surrounding sounds: the preposition у/в, the word for “and,” і/й, and the word for “from/with,” з/із/зі. Below, this article sets out those rules based on Український правопис (“the 2026 standard” below), which took effect as the state-language standard on March 28, 2026, the 2019 edition it is based on, the 4th edition of the orthography from 1993, and the descriptions in Українська мова. Енциклопедія (Ukrainian Language: An Encyclopedia, 2nd edition, 2004, compiled by the National Academy of Sciences of Ukraine’s Institute of Linguistics and Institute of the Ukrainian Language; “the encyclopedia” below) and the Academy’s dictionaries. Confirmed as of September 2026.

Why the Form Changes: Euphony

§23 through §25 of the 2026 standard all begin with the same reason: to avoid a hard-to-pronounce run of consonants or a run of vowels, for the sake of “милозвучність” (euphony).

The encyclopedia’s entry “Милозвучність” (euphony; by V. S. Kalashnyk) defines it as the power of a language’s sound system to resonate smoothly. As things that serve euphony in today’s written language, it lists variant word forms such as в — у — ув — уві — ві, від — од, з — зі — із, би — б, же — ж, і — й, and хоч — хоча, and calls this kind of example an “orthoepic alternation” (орфоепічне чергування). The same entry also states that Ukrainian is compared to Italian for its euphony, without saying who made the comparison.

Where to Use у, Where to Use в

§23 of the 2026 standard sets out the following for the preposition у/в and the word-initial у-/в-. The basic idea: use у to avoid a run of consonants, and в to avoid a run of vowels.

The standard also notes, in a footnote, unusual forms of у/в: уві/вві before a run of consonants (уві сні, “in a dream”), and, in literary works, ув before a vowel (ув очі).

Words Always Written With у, and Words Always Written With в

Some words have a fixed form regardless of the surrounding sounds. Paragraph 3 of §23 gives, as words always written with у: увага (attention), умова (condition), установа (institution), Угорщина (Hungary), and Умань (Uman), among others; and as words always written with в: влада (power), власний (one’s own), and вплив (influence), among others.

Some words distinguish у and в by meaning. The standard gives the pairs удача and вдача, уклад and вклад, управа and вправа, and уступ and вступ. Checking a dictionary, the 11-volume dictionary defines удача as “success, something going well,” and the 20-volume dictionary defines вдача as “a person’s character.” The standard notes, in a footnote, that the country name Україна has also been written Вкраїна in poetry.

This alternation also comes up when looking a word up in a dictionary. Looking up ВЗЯ́ТИ (to take) in the online edition of the 20-volume dictionary gives “див. узя́ти” (“see узяти”), with the actual definition under the у headword. The 11-volume dictionary gives the headword as “УЗЯТИ (ВЗЯТИ).” A word not found under в may be found under у, and vice versa. How to read dictionary headwords is covered in our article on how to use a Ukrainian dictionary, where typing лютого brings up “Lutheran”.

і and й

The word for “and,” і/й, and word-initial і-/й-, follow the same logic (§24).

• і: between two consonants (Вірю в пам’ять і серце людське, “I believe in memory and the human heart”); after a period, comma, or the like, before a consonant; at the start of a sentence or word (І долом геть собі село…, Shevchenko).
• й: between two vowels (У садку співали Ольга й Андрій); between a vowel and a consonant (Навчає баєчка великого й малого).
• The same applies at the start of a word: Він іде (he goes) versus Вона йде (she goes); Він, імовірно, … (he, probably, …) versus Висока ймовірність (a high probability).

However, і is always used when contrasting two things (батьки і діти, “parents and children”; правда і кривда, “truth and falsehood”), and before a word beginning with й, є, ї, ю, or я (Ольга і Йосип, Світлана і Єва). The standard also provides that after й, я, ю, є, or ї, either і or та is used for “and.”

з, із, зі, зо

The preposition з, meaning “from” or “together with,” has the forms із, зі, and зо (§25).

• з: before a vowel (Диктант з української мови, “a Ukrainian-language dictation”); at the start of a sentence, before a consonant (except з, с, ц and ж, ч, ш: З лісу потягло прохолодою); between a vowel and a consonant (я з любов’ю).
• із: mainly before a single letter з, с, ц, ж, ч, or ш (із золота, “of gold”; із села, “from the village”; із шовку, “of silk”).
• зі: before a run of consonants beginning with з, с, ш, and the like (зі школи, “from school”; зі Львова, “from Lviv”; зі зброєю, “carrying weapons”).
• зо: before два and три (2 and 3), and before мною (“with me”) (Проспав зо три години, “slept for about 3 hours”).

The standard notes that із and зі can sometimes both be correct, giving Тихович разом із сходом сонця… (Kotsiubynskyi) alongside Він устав разом зі сходом сонця (“he rose together with sunrise”).

Comparing the 1993, 2019, and 2026 Orthographies

This rule has changed slightly with each edition of the orthography. Here are the section numbers and content side by side.

From “Alternation” to “Usage”

Even the rule’s name has changed. §11 of the 1993 edition opens with “В українській мові чергуються … прийменники у, в” (“in Ukrainian, the prepositions у and в alternate…”). The encyclopedia, too, explains this phenomenon as a kind of “alternation” (чергування). The heading of §23 in the 2019 edition is “Позиції вживання прийменників і префіксів У та В” (“positions for using the prepositions and prefixes у and в”), and the 2026 standard’s is “Уживання прийменників У, В і початкових У-, В-” (“usage of the prepositions у, в and the word-initial у-, в-“). The 2026 standard does not call the word-initial у-/в- a “prefix” (префікс), but calls it “word-initial” (початкові).

Is у the Only Option at the Start of a Sentence?

Some points are treated differently between editions. §23 of the 2019 edition states that у is used at the start of a sentence or word before a consonant, giving only the example У лісі пахло квітами. The 2026 standard adds a footnote to the same item stating that “в and в- can also be used at the start of a sentence or word,” giving as examples В лісі пахло квітами, Вгорі яскраво сяяло сонце, and Внаслідок зливи пошкоджено дороги.

On the other hand, the Ministry of Culture describes the 2026 standard’s changes as editorial corrections — fixing typos and duplications, clarifying wording without changing the norm, adding examples, and removing examples of names connected to the aggressor state and its allies — and states that they do not affect the established orthographic rules as users know them. Bearing in mind which edition, 2019 or 2026, a piece of writing follows can reduce misreadings of у and в at the start of a sentence. How the 2019 orthography became the “state-language standard” seven years later in 2026 is covered in our article on that process.

Literary Works Can Depart From the Rule

Every edition of the orthography acknowledges that some writing departs from this rule. The 2019 edition gives the reason for departing from the у/в distinction as “the demands of rhythm or melody, or the author’s own preference for wording,” while the 2026 standard states that “in literary works, it may depart from this due to the demands of rhythm or melody.” The phrase “the author’s own preference for wording” does not appear in the 2026 standard. If you come across a form that departs from the rule in a poem or song lyric, it is not necessarily a typo.

The full picture of Ukrainian letters and sounds is also covered in our article on how Ukrainian and Russian differ.