Vowel Harmony: Rounded and Unrounded

Level 1

Turkish suffixes with 'high' vowels change their shape to match the word they attach to. There are four possible versions: -ı, -i, -u, or -ü.

How It Works

Four-Way Vowel Harmony is the practical result of applying both Palatal Harmony (Two-Way Vowel Harmony) and Labial Harmony (küçük ünlü uyumu). While Two-Way harmony only cares if a vowel is front or back, the Labial component also looks at whether your lips are rounded or flat.

This rule applies to many Turkish suffixes—specifically those containing 'high' vowels, often represented in textbooks as a capital -I. Common examples include the question particle, the accusative case, and the genitive case.

The Four Paths:

  • A or I in the stem leads to I in the suffix (e.g., kadın-ı)
  • E or İ in the stem leads to İ in the suffix (e.g., kedi-yi)
  • O or U in the stem leads to U in the suffix (e.g., okul-u)
  • Ö or Ü in the stem leads to Ü in the suffix (e.g., göl-ü)

Important Rules:

  • Rounding and Wide Vowels: While Four-Way harmony requires rounding to match, suffixes using Two-Way Vowel Harmony (like the plural suffix) only care about front/backness. This is why we say çocuk-lar even though 'u' is rounded.
  • The First Syllable Rule: In native Turkish words, the vowels 'o' and 'ö' only appear in the first syllable. If you see them later in a word, it is usually a loanword.
  • Loanword Exceptions: While suffixes usually follow the last vowel, some loanwords ending in palatalized consonants like 'l', 't', or 'k' take front-vowel suffixes instead (e.g., saat-i, alkol-ü, kalb-i).

Examples (4)

  1. Okulun kapısı açık.

    The door of the school is open.

    Word by Word: School-of door-its open.

    'Okul' ends in 'u', so the genitive suffix becomes '-un'. 'Kapı' ends in 'ı', so the possessive suffix becomes '-sı'.

  2. Bu senin kitabın mı?

    Is this your book?

    Word by Word: This your book-your [question]?

    The question particle 'mı' follows 'kitabın'. Since the last vowel in 'kitabın' is 'ı', the particle must be 'mı'.

  3. Dün çok güldü.

    He/she laughed a lot yesterday.

    Word by Word: Yesterday much laughed.

    The verb 'gülmek' (to laugh) has the vowel 'ü'. Therefore, the past tense suffix '-di' harmonizes to '-dü'.

  4. Süt içiyor musun?

    Are you drinking milk?

    Word by Word: Milk drinking [question]-you?

    The present continuous suffix '-iyor' always ends in 'o', so the following question particle must always be 'mu'.

Common Mistakes

  • Using 'i' or 'ı' after a rounded vowel (o, u, ö, ü).

    Gözin rengi mavi.
    Gözün rengi mavi.

    Because 'göz' (eye) contains the rounded vowel 'ö', the suffix must also be rounded. 'Gözin' is incorrect; it must be 'gözün'.

  • Trying to harmonize the '-yor' suffix.

    Gülüyör.
    Gülüyor.

    The 'o' in the present continuous suffix '-iyor' is fixed and never changes, even if the preceding vowel is 'ü'.

How It Connects

Tap a pattern to see what it builds on and what it leads to.

Vowel Harmony: Rounded and UnroundedLevel 1

Learn This First

To learn Four-Way Vowel Harmony, you must first be familiar with the Turkish alphabet's vowels and the basic concept of Two-Way Vowel Harmony, as this pattern further divides vowels into rounded and unrounded groups to determine suffix changes.

Learn Next

Patterns that build on this one.

And 13 more in the full list.