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I saw this image on reddit, and it made me wonder why the way Ukrainians say "knife" is different from all other Slavic languages?

  • Is this part of a more general trend ("i" instead of "o"), or just this word?
  • If it is, what caused this? Influence from other languages?
  • Is it a coincidence that Germanic languages also tend to have a "ni" here?
  • It would help if you state the word in the question, and the equivalents in some other Slavic languages, rather than forcing people to peer at a hard-to-read diagram (particularly hard to read if you have vision problems and rely on a screen reader).
    – Stuart F
    Oct 17, 2023 at 13:41
  • @StuartF It's "Niz" in Ukrainian, and it looks like some variation of "Noz" in all other Slav languages, except Czech, where it looks like "Nuz". Apparently some of those are diacritics, and pronounced differently, but this wasn't clear to me when I asked the question.
    – MWB
    Oct 17, 2023 at 21:03

2 Answers 2


This is one of the most salient and well-known features of Ukrainian, and the first mentioned in Wikipedia’s description of the history of the Ukrainian language; it is not just this word. The development is roughly that,

  • some time in the 12th or 13th century, before a consonant + weak yer, /e/ and /o/ were lengthened and raised to /iː/ and /uː/ (the weak yer was subsequently lost)
  • /uː/ (from /o/) was later fronted to /yː/, then unrounded to /iː/ so that the two eventually merged
  • later on, vowel length became non-phonemic, so now it’s just /i/

Note the conditioning, though: it only took place specifically before consonant + weak yer; the first stage can be summarised as

e, o > iː, uː / __Cə̆

Weak yer was very common at the end of various forms of words, but these words would also have other forms that had other vowels after the consonant and thus did not meet the criterion. This is why ніж only has і in the nominative and accusative singular: in all other cases, the vowel after the consonant was not a weak yer, so the first stage of the change never applied, and the vowel remained /o/: genitive ножa, instrumental ножeм, etc.

The same variation can be found in other words that originally ended in /oCə̆/, such as кіт (котa, котом).

The similarity between Ukrainian ніж and the Germanic words for ‘knife’ that also contain -ni- is pure coincidence: they come from different roots, and as noted above, the /i/ in Ukrainian is a regular sound change that also applies in other words.

  • It's still unclear to me why these changes occurred in Ukrainian, specifically, and not in other Slavic languages. Did some linguistically unusual circumstances exist in Ukraine?
    – MWB
    Oct 7, 2023 at 2:26
  • 7
    @MWB - Why do you think that Ukrainian is special and other Slavic languages has nothing like that? Don't you see Czech: nůž [nuːʃ], Polish: nóż [nuʂ], Slovak: nôž [nu̯oʃ]? A similar process happened to [o] in several languages, but went not far in Slovak [u̯o], further in Polish and Czech [u], and the furthest in Ukrainian [i], with some west Ukrainian dialects still having the intermediate-stage [y]. All the languages are different, the reason why a phonological change occurred in this language but not in that one is unanswerable in most cases.
    – Yellow Sky
    Oct 7, 2023 at 6:11
  • @YellowSky Are there other vowel or consonant shifts where some other Slav language is more advanced?
    – MWB
    Oct 8, 2023 at 6:34
  • 1
    There is a Lithuanian word knẽžas (“knife”), to which the Slavic nòžь can be cognate.
    – Anixx
    Oct 12, 2023 at 2:11
  • The Slavic word is not related to the Lithuanian word. Per Derksen 2008, the Slavic word is from PIE h1noǵh-io and cognate with Greek ἔγχος ‘spear’.
    – user41876
    Oct 16, 2023 at 20:50

Is this part of a more general trend ("i" instead of "o"), or just this word?

The former, and the phenomena of this has a name in Ukrainian liguistic terminology: ikavism.

If it is, what caused this? Influence from other languages?

It is assumed that the process of transition is associated with the reduction of vowel sounds and the emergence of closed syllables as a result. The vowels of full formation [o] and [e] in closed syllables received compensatory lengthening, turning into [i] through a series of intermediate stages. Obviously, this process began earliest in the Galician-Volyn dialect area, and from there it spread to other South Rusʼ dialects.

The decline of reduced and lengthening of etymological [o] and [e] in newly closed syllables were interdependent processes and occurred simultaneously. Lengthened vowels could not have existed in the language for a long time, because it contradicted the long-standing (since the time of quantum alignment) tendency to eliminate the opposition of vowels by duration. In different dialects of Ukrainian, lengthened vowels gave rise to different reflexes: in Polissja they changed into diphthongs or other sound combinations, in Galician-Volynian and southeastern dialects they gradually turned into.

The latter, due to the decline of reduced ъ and ь in the following syllable, lengthened through the stage of diphthongization (*о > [ō] > [uo], [uɪ], [ui], [ue] ... > [i]; *е > [ē] > [ie] > [i]) or through narrowing of these vowels into monophthongs and delabialization (*о, *е > [ō], [e] > [u], [ʊ̈] > [i]) in all southeastern and many southwestern dialects changed to [i]. The positional transition of [o], [e] to [i] caused the alternation of phonemes: [о] - [і], [е] - [і], and the expansion of the combinability of vowels and consonants, in particular palatalized consonant phonemes with the vowel [i]. Secondary [і] in newly closed syllables, in accordance with the old *о, *е, as well as [і] < ě (ѣ), is the norm of the modern Ukrainian literary language.

Is it a coincidence that Germanic languages also tend to have a "ni" here?

Just coincidence.

It's still unclear to me why these changes occurred in Ukrainian, specifically, and not in other Slavic languages.

It happened almost in all North Slavic languages too, with notable exceptions as Russian and Belarussian. Ukrainian just had more stages, if we compare the phenomena in other Slavic languages. I guess, you havnʼt note because of those diacritics.

  • English: a knife ~ [no] knife
  • Ukrainian: ніж ~ [немаʼ] ножа
  • Polish: nóż /nu…/ ~ noża /nɔ…/
  • Czech: nůž /nuː…/ ~ nože /no…/
  • Slovak: nôž /nu̯o…/ ~ noža /nɔ…/

For compare, one old [Ukrainian] Maksymovychʼs spelling has a spelling similar to those Slavic language where ніж would be as но̂ж.

  • So all Slavic languages are on the same path of vowel evolution, but Ukrainian's just ahead of others for some reason?
    – MWB
    Oct 7, 2023 at 7:37
  • 1
    @MWB North Slavic. And no, not necessarily the same path, but similar paths. Nobody knows what the future may bring; it’s possible Polish or Czech may at some point turn [u] into [y] and then [i] as well, but there’s no particular reason they should. Sound changes do not always have a reason – often they just happen. Oct 7, 2023 at 9:37

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