What does vowel harmony mean?
Vowel harmony is a pattern in which vowels within a word, or another defined part of a word, must share certain pronunciation features. These features may involve where the tongue is positioned, whether the lips are rounded, or the position of the tongue root. In a language with vowel harmony, the vowel in one syllable can therefore influence which vowels are allowed in other syllables.[1]
A simple example comes from Finnish. The word talo means “house,” and talossa means “in the house.” But kylä, meaning “village,” becomes kylässä, meaning “in the village.” Both words use the same grammatical ending, but the vowel in that ending changes from a to ä to agree with the vowels of the base word.[2]
The ending has not changed its meaning. It has changed its form to fit the sound pattern of the word. This is what makes vowel harmony particularly noticeable in languages that build words by adding suffixes or prefixes.
The central idea
Vowel harmony is about shared sound features, not identical vowels. The vowels in a word do not need to sound exactly alike. They need to agree in whichever feature the language’s harmony system requires.
What features can vowels share?
Vowels are produced by changing the shape of the vocal tract. A speaker can move the tongue toward the front or back of the mouth, raise or lower it, round the lips, or change the position of the tongue root. Different languages use different features to organize their vowels into harmonic groups.[3]
| Type of harmony | What the vowels agree on | Where it occurs |
|---|---|---|
| Front/back harmony | Whether the tongue body is positioned toward the front or back of the mouth. | Finnish, Turkish, Hungarian |
| Rounding harmony | Whether the vowels are pronounced with rounded or unrounded lips. | Turkish and parts of the Hungarian system |
| Tongue-root harmony | Whether the tongue root is advanced or retracted, often described using the feature [±ATR]. | Akan and several other African languages |
| Height harmony | How high or low the tongue body is during vowel production. | Various languages with vowel-height restrictions |
Two vowels can be different in several ways and still belong to the same harmonic group. For example, the Turkish vowels e and ü differ in rounding and height, but both count as front vowels. They therefore behave alike when a suffix needs to choose between a front and a back vowel.
Not every form of harmony uses all these features at once. A language may use only one, or use different features for different endings. Turkish provides an especially clear example of how two patterns can work together.
Vowel harmony in Turkish
Turkish has eight vowel letters: a, e, ı, i, o, ö, u, ü. For the most basic type of vowel harmony, they are divided into two groups. The back vowels are a, ı, o, u; the front vowels are e, i, ö, ü. The dotless ı is a separate vowel from dotted i, not a spelling variation.[4]
Two-way harmony: -lar or -ler
To make many Turkish nouns plural, a speaker uses either -lar or -ler. The choice depends on the last vowel of the word. A back vowel calls for -lar; a front vowel calls for -ler. This is called two-way vowel harmony because the suffix has two vowel choices.
| Base word | Last vowel | Plural | Meaning |
|---|---|---|---|
| kitap | a (back) | kitaplar | books |
| okul | u (back) | okullar | schools |
| ev | e (front) | evler | houses |
| göz | ö (front) | gözler | eyes |
Four-way harmony: -ı, -i, -u or -ü
Other Turkish suffixes are more selective. They must match both the front/back quality of the preceding vowel and whether that vowel is rounded. The vowel in these suffixes can take four forms: ı, i, u, or ü. Linguists and grammar books call this four-way vowel harmony.[4]
| Last vowel of the base | Suffix vowel | “My …” example |
|---|---|---|
| a, ı (back, unrounded) | ı | kız → kızım (“my daughter”) |
| e, i (front, unrounded) | i | ev → evim (“my house”) |
| o, u (back, rounded) | u | kol → kolum (“my arm”) |
| ö, ü (front, rounded) | ü | göz → gözüm (“my eye”) |
The meaning of the possessive ending remains “my” throughout the table. Its vowel changes only because of the sound environment. As more suffixes are added, each harmonizing suffix normally responds to the relevant vowel in the form immediately before it. Not every Turkish ending alternates, however, and loanwords can have vowel combinations that do not follow the simplest native-word pattern.[4]
Vowel harmony in Finnish
Finnish also has front/back vowel harmony, but it treats two vowels differently from Turkish. Its eight vowels can be arranged into three groups. The back vowels are a, o, u; the front harmony vowels are ä, ö, y; and e, i are usually described as neutral vowels.[2]
Within an ordinary native Finnish word, vowels from the back and front harmony groups generally do not mix. The neutral vowels e and i are different: they can appear alongside either group. If a word contains only neutral vowels, harmonizing endings normally take their front-vowel forms.
| Base word | Ending | Completed word | Meaning |
|---|---|---|---|
| talo (house) | -ssa | talossa | in the house |
| kylä (village) | -ssä | kylässä | in the village |
| metsä (forest) | -ssä | metsässä | in the forest |
| kieli (language) | -ssä | kielessä | in the language |
The word metsä contains both a neutral vowel (e) and a front vowel (ä). The neutral vowel does not prevent the suffix from taking the front form -ssä. Similarly, kieli contains only neutral vowels, so it also takes -ssä.
Finnish compounds show why it is important to describe harmony as a rule operating within a particular domain, rather than an absolute ban on certain letters appearing in the same written word. Different parts of a compound may have different vowel patterns, and the suffix generally harmonizes with the final part. Loanwords can also behave differently from long-established native words.[2]
How Hungarian vowel harmony works
Hungarian has a productive front/back harmony system and a more limited rounding harmony system. Like Finnish and Turkish, it often changes a suffix vowel to suit the word it attaches to. For example, the ending meaning “in” appears as -ban after many back-vowel words and -ben after many front-vowel words.[5]
Hungarian becomes especially interesting when a word contains vowels that are phonetically front but do not always force a front-vowel suffix. In words such as zokni (“sock”), the final i may be transparent to harmony. The form zoknitól (“from the sock”) uses the back-vowel suffix -tól, following the earlier back vowel o rather than the closer i.[6]
This does not mean that every Hungarian front unrounded vowel behaves in exactly the same way. The degree of transparency varies with vowel quality, word structure, and particular lexical items. Hungarian is an important example of why vowel harmony cannot always be reduced to a single rule such as “look at the last vowel.”[5]
Vowel harmony beyond front and back vowels
The best-known classroom examples often come from Turkish, Finnish, and Hungarian. However, vowel harmony is found in language families across different parts of the world. The feature being shared is not always tongue-body frontness or lip rounding.[3]
Tongue-root harmony in Akan
Akan, spoken in Ghana, has a harmony system involving advanced tongue root, abbreviated ATR. During the production of a [+ATR] vowel, the tongue root is advanced; in a [−ATR] vowel, it is not advanced in the same way. Many Akan words favor vowels belonging to one ATR set rather than mixing the two sets.
For example, researchers describe Akan kube (“coconut”) as a word with [+ATR] vowels, while ɛkɔm (“hunger”) illustrates the [−ATR] group. In this system, the harmony relationship depends on a property of the tongue root, not simply whether the vowels are at the front or back of the mouth.[7]
Other languages show still different combinations of vowel features and grammatical boundaries. These differences are important because they show that vowel harmony names a family of related sound patterns, not one identical rule shared by every language.
How far can vowel harmony spread?
Vowel harmony can connect vowels that are separated by consonants and even by other vowels. The sounds do not need to sit directly next to each other. In Turkish kitaplar, for instance, the a of the plural ending agrees in backness with the final vowel of kitap, despite the intervening consonants. Linguists call this kind of relationship a long-distance phonological dependency.[8]
The region in which harmony operates is called its domain. Depending on the language, that domain might be a root, a stem plus certain endings, or a phonological word. Some systems are controlled by a stem that determines the vowels of its affixes. Others involve a particular vowel feature that spreads regardless of whether its source is in a root or an affix.[1]
Two useful terms
A trigger is the vowel whose feature influences another vowel. A target is the vowel that changes or is restricted by the harmony rule. In a typical Turkish plural, the stem’s last vowel is the trigger and the suffix vowel is the target.
Harmony may work from left to right, from right to left, or in more complex directions. Consonants often stand between the participating vowels without affecting the process. The exact boundaries and direction are properties of the individual language, not part of a universal one-size-fits-all rule.
Do all vowels in a word have to match?
No. The phrase “vowels in a word agree” is a useful starting point, but it describes the simplest cases rather than every vowel harmony system. Linguists distinguish several ways that a vowel may behave in relation to a harmony process.
| Term | What it means | Example or effect |
|---|---|---|
| Harmonic vowel | Participates in the relevant agreement pattern. | Finnish ä in kylässä belongs to the front group. |
| Transparent vowel | Can occur between a trigger and a target without preventing harmony from continuing. | Hungarian i in zoknitól does not force a front suffix. |
| Opaque vowel | Blocks the influence of another vowel, or becomes the relevant source for the following vowel. | Its presence changes which harmonic feature can reach a later target. |
| Invariant vowel | Does not alternate, even where other affix vowels do. | Some Turkish suffixes retain a fixed vowel. |
Compounds and borrowed words may also mix vowel sets that do not ordinarily occur together within simple native roots. These are not necessarily mistakes. They show that harmony is sensitive to word history, grammatical structure, and the specific pattern used by a language.[1]
Vowel harmony, assimilation, and coarticulation
Vowel harmony is closely related to assimilation, the broader process in which one speech sound becomes more like another. In many accounts, vowel harmony is a type of assimilation involving a particular vowel feature across a defined domain. But it is not the same thing as every small change caused by neighboring sounds.[3]
| Process | Main idea | Typical scale |
|---|---|---|
| Coarticulation | Articulatory movements for neighboring sounds overlap during speech. | Often gradual, involving nearby sounds and their transitions. |
| Assimilation | A sound becomes more similar to another in a particular context. | May be local or longer-distance; may involve vowels or consonants. |
| Vowel harmony | Vowels agree in a specified feature within a phonological or morphological domain. | Can connect vowels across syllables or affix boundaries. |
Coarticulation can help explain how some harmony patterns arise, but the two concepts are not interchangeable. Coarticulation describes overlapping speech movements; vowel harmony describes a systematic part of a language’s sound pattern, often visible in which suffix forms speakers select.[8]
Does English have vowel harmony?
Modern Standard English does not have a productive, general vowel harmony system like Turkish or Finnish. English words can contain very different vowel qualities without requiring them to belong to one harmonic group. A word such as telephone, for instance, does not require its vowels to match in frontness or rounding.[11]
English does have other kinds of vowel changes. The difference between sing and sang is traditionally analyzed as a form of ablaut, an alternation associated with a grammatical distinction. It is not evidence of word-wide vowel harmony. The distinction matters because the mere presence of alternating vowels does not mean that a language has a harmony rule.[9]
Why vowel harmony matters
For someone learning Turkish, Finnish, or Hungarian, vowel harmony is a practical part of grammar. It helps determine which suffix to use, how to pronounce a longer word, and why two forms that mean the same thing sound slightly different. Learning the relevant vowel groups can reduce the amount of memorization required for individual endings.
For linguists, harmony is a way to investigate how sound patterns extend beyond adjacent sounds. The choice of one vowel can depend on another vowel several syllables away, and the pattern may interact with word structure, neutral vowels, and historical changes.[1]
It can matter for listening, too. In experiments, Finnish listeners used mismatches in vowel harmony as one cue for locating word boundaries in continuous speech. A stretch of sounds that breaks the expected harmony pattern can suggest that one word has ended and another has begun. This does not make harmony a perfect boundary marker, but it shows that the pattern can contribute to real-time speech perception.[10]
Researchers have also found sensitivity to harmony patterns in English-learning infants, despite English lacking a productive vowel harmony system. The finding suggests that detecting recurring relationships between vowels may be a useful capacity in early speech learning, rather than simply a skill acquired by speakers of vowel-harmony languages.[11]
Sources
- [1]van der Hulst, Harry. “Vowel Harmony.” Oxford Research Encyclopedia of Linguistics, Oxford University Press, 2016. Read the source
- [2]Korpela, Jukka K. “Vowel Harmony.” Handbook of Finnish, 2nd ed. Read the source
- [3]McCollum, Adam G. “Vowel Harmony.” International Encyclopedia of Language and Linguistics, 3rd ed., Elsevier, 2026. Read the source
- [4]“Vowel Harmony.” Turkish Textbook. Read the source
- [5]Törkenczy, Miklós. “Hungarian Vowel Harmony.” Oxford Bibliographies in Linguistics, Oxford University Press, 2016, updated 2021. Read the source
- [6]“Articulatory Characteristics of Hungarian ‘Transparent’ Vowels.” Research article archived in PubMed Central. Read the source
- [7]“Tongue Root Harmony Cues for Speech Segmentation in Multilingually Raised Infants Learning Languages With and Without Vowel Harmony in Ghana.” Bilingualism: Language and Cognition, Cambridge University Press. Read the source
- [8]Nevins, Andrew. “What Is Vowel Harmony, How Does It Vary, and Why Study It?” In Locality in Vowel Harmony, MIT Press, 2010. Read the source
- [9]“Ablaut.” The Concise Oxford Companion to the English Language, reproduced by Encyclopedia.com. Read the source
- [10]Suomi, Kari, James M. McQueen, and Anne Cutler. “Vowel Harmony and Speech Segmentation in Finnish.” Journal of Memory and Language, 1997. Read the source
- [11]Mintz, Toben H., Rachel L. Walker, Ashlee Welday, and Celeste Kidd. “Infants’ Sensitivity to Vowel Harmony and Its Role in Segmenting Speech.” Cognition, 2018. Read the source