Turkish Vowel Harmony: The Complete Guide to 2-Way & 4-Way Harmony

Vowel harmony (ünlü uyumu) is the rule that makes Turkish suffixes change shape: the plural is -lar in kitaplar (books) but -ler in evler (houses); the accusative is -ı, -i, -u or -ü depending on the word. Every case ending, possessive and verb suffix follows it, so it is the first system to master. The good news is that you only ever need to look at one vowel, the last vowel of the word you are adding to, and there are only two patterns to learn. This guide explains the vowel grid behind the rules, both patterns with tables, which suffixes follow which, and the small set of genuine exceptions.

The eight vowels

Turkish vowels can be sorted by three features: front or back, rounded or unrounded, low (open) or high (closed).

• 2-way harmony only cares about front vs back.
• 4-way harmony cares about front vs back and rounded vs unrounded.

If the letters ı, ö and ü are still new to you, start with the alphabet and pronunciation guide.

2-way harmony: a or e

Suffixes with a/e in their basic form have two variants:

Common 2-way suffixes

The locative -da/-de and ablative -dan/-den are 2-way, never 4-way: okulda (at school), never ❌ okuldu in this meaning.

4-way harmony: ı, i, u or ü

Suffixes with a high vowel (ı, i, u, ü) have four variants. The suffix vowel keeps the front/back quality and the rounding of the last vowel, but is always high:

Common 4-way suffixes

• Cases: accusative -(y)ı (evi, kapıyı), genitive -(n)ın (evin, kapının)
• Possessives: -(ı)m, -(ı)n, -(s)ı, -(ı)mız, -(ı)nız (evim, okulun, gözümüz); see possessive suffixes
• Question particle: mı, mi, mu, mü
• “To be” endings: -(y)ım, -sın, -(y)ız, -sınız, -dır (yorgunum, hastasın)
• Verb tenses: past -dı (geldi, yaptı, okudu, gördü), reported past -mış, present continuous -ıyor
• Derivational suffixes: -lı, -sız, -lık, -cı (tuzlu, şekersiz, gözlük, sütçü); see adjective suffixes

Putting it together: chains of suffixes

Each suffix looks at the vowel directly before it, which may belong to a previous suffix:

• ev + ler + im + de → evlerimde (in my houses): -ler follows e; -im follows e; -de follows i.
• okul + lar + ımız + dan → okullarımızdan (from our schools): -lar follows u; -ımız follows a; -dan follows ı.
• gör + dü + nüz + mü → gördünüz mü? (did you see?)

Buffer letters (y, n, s) and consonant changes (kitap → kitabı) happen at the same time; see buffer letters and consonant mutation. You can test any word in the harmony calculator.

Harmony inside words

Turkish grammars also describe harmony within a word:

• Büyük ünlü uyumu (front/back harmony): native words usually have only back or only front vowels: kapı, arkadaş, çocuk; gelecek, güzel, öğrenci.
• Küçük ünlü uyumu (rounding harmony): after the first syllable, o and ö normally don’t appear in native words; this is why the suffixes never contain o/ö, with the single exception of the -yor in geliyor.

Many words break the front/back rule: native words such as anne (mother), elma (apple), kardeş (sibling) and hangi (which), and countless loanwords such as kitap, kalem, otobüs, televizyon. This never affects the suffix: it always follows the last vowel: kalemler, otobüsü, televizyonlar, annem, elmalar.

Real exceptions

Loanwords that take front suffixes

A small set of loanwords, mostly from Arabic and French, end in a back vowel + consonant but take front suffixes. This reflects how the final syllable was pronounced in the source language (a “front” or palatal consonant), not anything you can see in the spelling. Learn them as vocabulary:

Suffixes that don’t harmonise

• -ken “while”: çalışırken (while working), küçükken (when I was little)
• -ki “the one in/of”: akşamki (the evening one), masadaki (the one on the table); but dünkü and bugünkü
• -leyin “in the …”: sabahleyin (in the morning), akşamleyin (in the evening)
• -gil “X’s family”: annemgil (my mum’s family)
• -yor: the -yor part of the present continuous is fixed; only the vowel before it changes. See present continuous.

Example words and sentences

1. Kitaplar masada. — The books are on the table. (-lar, -da)
2. Evde misin? — Are you at home? (-de, mi)
3. Okulu çok seviyorum. — I really love the school. (-u)
4. Gözlüğüm nerede? — Where are my glasses? (-üm)
5. Kapıyı kapat, lütfen. — Close the door, please. (-yı)
6. Annemle konuştum. — I talked with my mother. (-le)
7. Otobüsü kaçırdım. — I missed the bus. (-ü)
8. Saatler çok pahalı. — The watches are very expensive. (exception)
9. İstanbul’da yaşıyorum. — I live in Istanbul. (-da)
10. Türk müsünüz? — Are you Turkish? (mü + -sünüz)
11. Şekersiz çay lütfen. — Tea without sugar, please. (-siz)
12. Dün geldiler. — They came yesterday. (-di, -ler)
13. Arkadaşlarımızdan haber aldık. — We heard from our friends. (-lar, -ımız, -dan)
14. Bugünkü toplantı iptal. — Today’s meeting is cancelled. (-kü)
15. Sabahleyin koşarım. — I run in the mornings. (-leyin)
16. Bu harfi nasıl okuyoruz? — How do we pronounce this letter? (exception)

Common mistakes

• Looking at the first vowel: ❌ otobüslar / ✅ otobüsler.
• Treating the locative as 4-way: ❌ okuldu (for “at school”) / ✅ okulda.
• Using 2-way vowels in a 4-way suffix: ❌ evlerem / ✅ evlerim.
• Over-applying exceptions: the saat-group is small; kitap → kitaplar, kalem → kalemler are regular.
• Harmonising invariable suffixes: ❌ çalışırkan, sabahlayın / ✅ çalışırken, sabahleyin.

Mini-exercise

Add the suffix in brackets.

1. masa + (plural)
2. göz + (accusative)
3. okul + (locative)
4. kedi + (question particle)
5. çocuk + (plural) + (“my”)
6. saat + (plural)
7. üzüm + (ablative)
8. kapı + (genitive)

Answers: 1. masalar 2. gözü 3. okulda 4. kedi mi 5. çocuklarım 6. saatler 7. üzümden 8. kapının

Next steps

Check your own words in the harmony calculator, then see how harmony combines with endings in the noun cases guide and with consonant changes in the ketçap rule.