Vowel harmony is one of the most fundamental and important aspects of Turkish grammar. Turkish words generally obey two vowel harmony rules, called the major vowel harmony and the minor vowel harmony.

These rules change the vowels in the suffixes added to words. A good understanding of these rules is necessary to be able to use suffixes, hence to be able to make correct and meaningful sentences.

3. Practical notes about vowel harmony rules

As far as vowel harmony is concerned, we can separate all the suffixes in Turkish into two main groups. Thinking in terms of these two cases simplifies these seemingly complicated rules. These are:

Case 1:

The suffixes with first vowel -i (the suffixes -i, -di, -iyor, -im, -in ...)

Case 2:

suffixes with first vowel -e (the suffixes -e, -de, -den, -erek, ...)

All suffixes with first vowel -i, -ı, -u, -ü fall into the first group, and they are different forms of this case modified according to vowel harmony rules.

bal-ım --> balım (my honey)

ev-im --> evim (my home)

sınıf-im --> sınıfım (my class)

dil-im --> dilim (my tongue)

sol-im --> solum (my left)

göz-im --> gözüm (my eye)

okul-im --> okulum (my school)

üzüm-im --> üzümüm (my grape)

All suffixes with first vowel -e, -a fall into the second group, and they are different forms of this case modified according to vowel harmony rules.

araba-den --> arabadan (from the car)

ev-den --> evden (from home)

kapı-den --> kapıdan (from the door)

deniz-den --> denizden (from the sea)

sol-den --> soldan (from the left)

göz-den --> gözden (from the eye)

okul-den --> okuldan (from school)

kapı-den --> kapıdan (from the door)

Note that no suffix has -o or -ö as the first vowel. Actually, no suffix has the letter -ö in it and there is only one suffix that has the vowel -o (this is the suffix for present continuous tense, -iyor and this -o does not change according to any vowel harmony rules).

bak-iyor --> bakıyor (he/she/it is looking)

gel-iyor --> geliyor (he/she/it is coming)

sık-iyor --> sıkıyor (he/she/it is squeezing)

bil-iyor --> biliyor (he/she/it knows)

koş-iyor --> koşuyor (he/she/it is running)

gör-iyor --> görüyor (he/she/it is seeing)

bul-uyor --> buluyor (he/she/it is finding)

gül-iyor --> gülüyor (he/she/it is laughing)

The suffixes in case 1 are affected from both the major vowel harmony and the minor vowel harmony. For example, the suffix -di can become -di, -dı, -du or -dü depending on the word at which it is appended.

ara-di --> aradı

gel-di --> geldi

kır-di --> kırdı

bil-di --> bildi

sol-di --> soldu

gör-di --> gördü

bul-du --> buldu

üşü-di --> üşüdü

The suffixes in case 2 are affected by only the major vowel harmony rule. For example, the suffix -erek can become -erek or -arak depending on the word at which it is appended.

bak-erek --> bakarak (with looking)

sev-erek --> severek (with loving)

sık-erek --> sıkarak (with squeezing)

bil-erek --> bilerek (with knowing, knowingly)

koş-erek --> koşarak (with running)

gör-erek -- görerek (with seeing)

vur-erek -- vurarak (with hitting)

bük-erek -- bükerek (with bending)