In phonology, vowel harmony is a phonological process in which vowels assimilate ("harmonize") to share certain distinctive features. Vowel harmony is often confined to the domain of a phonological word, but may extend across word boundaries in certain languages.
Generally, one vowel will trigger a shift in other vowels within the domain, such that the affected vowels match the relevant feature of the trigger vowel. Intervening segments are common between affected vowels, meaning that the vowels do not need to be next to each other for this change to apply. This is classified as a "long-distance" type of assimilation. Common phonological features that define the natural classes of vowels involved in vowel harmony include vowel backness, vowel height, nasalization, roundedness, and advanced and retracted tongue root.
Certain authors and articles use the term vowel harmony to refer to progressive (beginning-to-end) vowel assimilation, and use umlaut to refer to regressive assimilation. The term umlaut is also used in a different sense to refer to a type of vowel gradation, as well as the diacritic that often marks such changes. Metaphony is often used synonymously with vowel harmony, but is typically used to describe historical sound changes. This article uses the term "vowel harmony" to refer to both progressive and regressive assimilatory processes.
Vowel harmony is found in many agglutinative languages. The given domain of vowel harmony taking effect often spans across morpheme boundaries, and suffixes and prefixes will usually follow vowel harmony rules. Vowel harmony is also considered an areal feature in some parts of the world, especially Northern and Central Asia among the Turkic, Mongolic, and Tungusic language families, as well as other languages in contact with languages from the aforementioned families.
"Long-distance" Vowel harmony processes are "long-distance" in the sense that the assimilation involves sounds that are separated by intervening segments (usually consonant segments). In other words, harmony refers to the assimilation of sounds that are not adjacent to each other. For example, a vowel at the beginning of a word can trigger assimilation in a vowel at the end of a word. The assimilation occurs across the entire word in many languages. This is represented schematically in the following diagram:
{| cellspacing="5" style="font-size: 110%;" ! beforeassimilation
! afterassimilation
| VaCVbCVbC | → | VaCVaCVaC | (Va = type-a vowel, Vb = type-b vowel, C = consonant)
In the diagram above, the Va (type-a vowel) causes the following Vb (type-b vowel) to assimilate and become the same type of vowel (and thus they become, metaphorically, "in harmony"). This property of vowel harmony to apply to non-adjacent segments has been used to argue for the autosegmental phonology framework, where vowels constitute a tier that operate independently of other segments.
The vowel that causes the vowel assimilation is frequently termed the trigger while the vowels that assimilate (or harmonize) are termed targets. When the vowel triggers lie within the root or stem of a word and the affixes contain the targets, this is called stem-controlled vowel harmony (the opposite situation is called dominant).van der Hulst, H., & van de Weijer, J. (1995). Vowel harmony. In J. A. Goldsmith (Ed.), The handbook of phonological theory (pp. 495–534). Oxford: Blackwell. This is fairly common among languages with vowel harmony and may be seen in the Hungarian dative suffix:
{| cellspacing="5" ! Root ! Dative ! Gloss
| 'city'
| 'joy'
The dative suffix has two different forms . The form appears after the root with back vowels ( and are back vowels). The form appears after the root with front vowels ( and are front vowels).
Features of vowel harmony
Vowel harmony often involves dimensions such as:
Rose & Walker (2011) Ko (2018)Ko, S., Joseph, A., & Whitman, J. (2014). Comparative consequences of the tongue root harmony analysis for proto-Tungusic, proto-Mongolic, and proto-Korean. In M. Robbeets & W. Bisang (Eds.). Paradigm Change: In the Transeurasian languages and beyond (pp. 141-176). Philadelphia, PA: John Benjamins.Ko, S. (2011). Vowel contrast and vowel harmony shift in the Mongolic languages. Language Research, 47(1), 23-43. Dimension Value Backness Harmony Palatal harmony Vowel backness back or front, [±back] Roundedness Harmony Labial harmony Roundedness rounded or unrounded, [±round] Height Harmony Height harmony Vowel height high or low, [±high] Tongue Root Harmony Tongue root harmony Advanced and retracted tongue root advanced or retracted, [±ATR]
Nasalization, as in Guaraní, where the presence of nasal vowels causes other vowels to become nasalized as well. There are systems in which the presence of a nasal consonant triggers vowels to become nasal, but this is technically classified as a type of vowel–consonant harmony. Rhoticity, like in Yurok. Unconventional systems, like the one in Nez Perce, that do not seem to be based on any obvious phonetic feature at first.
Some languages have more than one system of harmony. For instance, many languages of the Altaic sprachbund are proposed to have a rounding harmony superimposed over a backness harmony.
Even among languages with vowel harmony, not all vowels need to participate in the vowel conversions; these vowels are termed neutral. Neutral vowels may be opaque and block harmonic processes or they may be transparent and not affect them. Intervening consonants are also often transparent.
Languages that do have vowel harmony often allow for lexical disharmony, or words with mixed sets of vowels even when an opaque neutral vowel is not involved. Van der Hulst & van de Weijer (1995) point to two such situations: polysyllabic trigger morphemes may contain non-neutral vowels from opposite harmonic sets, and certain target morphemes simply fail to harmonize. Many loanwords exhibit disharmony, such as Turkish , ('time' [from Arabic ]); * would have been expected. Finnish ('Olympic games') and ('secondary') have both front and back vowels, and are pronounced accordingly in standard Finnish, but many speakers intuitively apply vowel harmony – , and or .
Languages with vowel harmony
Turkic languages Turkic languages inherit their systems of vowel harmony from Proto-Turkic, which already had a fully developed system. The one exception is Uzbek, which has lost its vowel harmony due to extensive Persian influence; however, its closest relative, Uyghur, has retained Turkic vowel harmony.
Azerbaijani Azerbaijani's system of vowel harmony applies on both the front/back and rounded/unrounded dimensions.
Azerbaijani Vowel Harmony Front Back Unrounded Rounded Unrounded Rounded Vowel e, ə, i ö, ü a, ı o, u Two form suffix (iki şəkilli şəkilçilər) ə a Four form suffix (dörd şəkilli şəkilçilər) i ü ı u
Tatar Tatar has no neutral vowels. The vowel é is found only in loanwords. Other vowels also could be found in loanwords, but they are seen as back vowels. Tatar also has rounding harmony, but this is not represented in writing. O and ö could be written only in the first syllable, but vowels they mark could be pronounced in the place where ı and e are written.
Front ä e i ö ü Back a ı í o u é
Kazakh Kazakh's system of vowel harmony is primarily a front/back system, but there is also a system of rounding harmony that is not represented by the orthography.
Kyrgyz Kyrgyz's system of vowel harmony is primarily a front/back system, but there is also a system of rounding harmony, which strongly resembles that of Kazakh.
Turkish Turkish has a 2-dimensional vowel harmony system, where vowels are characterised by two features: [±front] and [±rounded]. There are two sets of vocal harmony systems: a simple one and a complex one. The simple one is concerned with the low vowels and has only the [±front] feature ( front vs back). The complex one is concerned with the high vowels and has both [±front] and [±rounded] features ( front unrounded vs front rounded and back unrounded vs back rounded). The close-mid vowels are not involved in vowel harmony processes.
+Turkish vowel harmony Front Back Unrounded Rounded Unrounded Rounded Vowel e /e/ i /i/ ö /ø/ü /y/ a /a/ ı /ɯ/ o /o/u /u/ Simple system e a Complex system i ü ı u
Front/back harmony Turkish has two classes of vowelsfront and back. Vowel harmony dictates that words may not contain both front and back vowels. Therefore, most grammatical suffixes come in front and back forms, e.g. 'in Turkey' but 'in Germany'.
+Turkish vowel harmony examplesExamples from Nom.sg Gen.sg. Nom.pl Gen.pl. Gloss 'rope' 'hand' 'girl'
Rounding harmony In addition, there is a secondary rule that and in suffixes tend to become and respectively after rounded vowels, so certain suffixes have additional forms. This gives constructions such as 'it is Turkey', 'it is the door', but 'it is the day', 'it is the watermelon'.
Exceptions Not all suffixes obey vowel harmony perfectly.
In the suffix , the is invariant, while the changes according to the preceding vowel; for example – 'he/she/it fades'. Likewise, in the suffix , the is invariant: – 'When in Rome'; and so is the in the suffix : – 'credible'. The suffix exhibits partial harmony, never taking a back vowel but allowing only the front-voweled variant : – 'belonging to yesterday'; – 'belonging to tomorrow'.
Most Turkish words have vowel harmony not only for suffixes, but also internally. However, there are many exceptions.
Compound words are considered separate words with respect to vowel harmony: vowels do not have to harmonize between members of the compound (thus forms like "this|day" = 'today' are permissible). Vowel harmony does not apply for loanwords, as in – from French ''. There are also a few native modern Turkish words with unharmonized vowels (such as 'mother' or 'sibling' which used to obey vowel harmony in their older forms, and , respectively). However, in such words, suffixes nevertheless harmonize with the final vowel; thus – 'his/her mother', and – 'volleyballer'.
In some loanwords the final vowel is an , , or and thus looks like a back vowel, but is phonetically actually a front vowel, and governs vowel harmony accordingly. An example is the word , meaning 'hour' or 'clock', a loanword from Arabic. Its plural is . This is not truly an exception to vowel harmony itself; rather, it is an exception to the rule that denotes a front vowel.
Disharmony tends to disappear through analogy, especially within loanwords; e.g. (a man's name) < earlier , from Arabic ; 'Moslem, Muslim (adj. and n.)' < Ottoman Turkish , from Persian .
Tuvan Tuvan has one of the most complete systems of vowel harmony among the Turkic languages.Smolek, Amy (2011). Vowel Harmony in Tuvan and Igbo: Statistical and Optimality Theoretic Analyses. Undergraduate Thesis, Swarthmore College https://www.swarthmore.edu/sites/default/files/assets/documents/linguistics/2011_Smolek.pdf
Mongolic languages Mongolic languages display various vowel harmony systems. While there is some debate, Proto-Mongolic appears to have had a system of backness harmony, from which the modern languages' systems descend.
Mongolian