Vokaaliharmoniaan

Vokaaliharmoniaan, or vowel harmony, is a phonological process in which vowels within a word or its morphological parts harmonize to share certain phonetic features, most commonly backness (front versus back vowels) and sometimes rounding. In languages with vowel harmony, affixes adapt their vowels to match the stem’s vowels, producing a cohesive vocalic pattern across a word.

The mechanism is most visible in agglutinative languages, where many suffixes are added to a stem and must harmonize with the stem’s vowel inventory. A suffix may change its internal vowels so that the entire word sounds cohesive. This can affect plurality, case endings, possessives and other derivational suffixes.

Turkish is a well-known example of strong vowel harmony. Suffix vowels change according to the last vowel of the stem. For instance, ev (house) takes evler (houses) with a front vowel in the suffix, while kitap (book) takes kitaplar (books) with a back vowel in the suffix. Possessive suffixes also harmonize: evim (my house) uses a front vowel, whereas kitabım (my book) uses a back vowel in the suffix.

Finnish also exhibits vowel harmony, though it interacts with other phonological rules. In Finnish, suffix vowels harmonize with the stem’s vowels: words with back vowels tend to take back-vowel suffixes, while those with front vowels take front-vowel suffixes. Neutral vowels e and i can appear in either set and do not block harmony.

Other languages with vowel harmony include Hungarian, Azerbaijani, Mongolian, and several Turkic and Uralic languages. The specifics—which vowels participate, how many features are harmonized, and how strictly neutral vowels behave—vary by language.