what is it?
Vowel harmony is a rule that determines which vowel appears in a suffix based on the last vowel of the word stem. Turkish has two harmony patterns: 2-way harmony (e/a) for low vowels and 4-way harmony (i/ı/u/ü) for high vowels. When you add a suffix, you choose the vowel that harmonises with the stem so the word flows naturally.
when to use it
Apply vowel harmony whenever you attach a suffix to a Turkish word. The harmony rule applies to:
Plural suffixes (-ler/-lar)
Case markers (accusative, dative, locative, ablative)
Possessive suffixes
Verb conjugations
Most other suffixes in Turkish
formation
Look at the last vowel of the stem and choose the suffix vowel according to these patterns:
2-way harmony (e/a) — for low vowels in suffixes:
| Last vowel of stem | Suffix vowel | Example |
|---|---|---|
| e, i, ö, ü (front vowels) | e | ev → evler |
| a, ı, o, u (back vowels) | a | okul → okullar |
4-way harmony (i/ı/u/ü) — for high vowels in suffixes:
| Last vowel of stem | Suffix vowel | Example |
|---|---|---|
| e, i (front unrounded) | i | ev → evi |
| a, ı (back unrounded) | ı | kapı → kapısı |
| o, u (back rounded) | u | okul → okulu |
| ö, ü (front rounded) | ü | göl → gölü |
examples in context
common pitfalls
Defaulting to one vowel form. Many learners use -ler for all plurals because it is taught first. Remember that okullar is correct, not *okuller. Always check the last vowel of the stem before choosing the suffix.
Treating loanwords as front-vowel words. Some borrowed words contain front vowels but take back-vowel suffixes because Turkish treats them as back-vowel stems. For example, oteller (hotels) uses -ler, but lokaller may be lokallar depending on usage. Learn loanword harmony patterns as you encounter them.
Three sentences, graded here. Nothing is saved and no account is needed.
Ahmet dün akşam maç ___ izledi. (maç)
Fill in the blank with the correct form of the word in parentheses.