Vowel harmony is essential to learn in order to speak Turkish well, however at first it is quite hard to understand, so i will try to make this guide as simple to understand as possible!
In Turkish there are 8 vowels. We can split these into 2 groups. These are:
e, i, ö, ü (known as 'front' vowels)
a, ı , o, u (known as 'back' vowels)
It is essential to learn which vowels go into which group. To make this easier, think of them as the 'e dotted group' (which contains 'e' and the 3 vowels with dots), and the 'a undotted group' (which contains the 'a' and the 3 undotted groups).
Many suffixes are also split into two, for example '-den/-dan' (from), '-de/-da' (in/on/at), and '-(y)e/-(y)a'(to). Vowel harmony insures that the correct suffix is used depending on what the last vowel in the word is.
If the last letter is a 'front' vowel, then '-den', '-de', and '-(y)e' would be used. If the last letter is a 'back' vowel, then '-dan', '-da', and '-(y)a' would be used.
Examples
ev (house)
from the house (evden)
in the house (evde)
to the house (eve)
car (araba)
from the car (arabadan)
in the car (arabada)
to the car (arabaya)
Click here to test yourself on 'Vowel Harmony 1'
Click here to go to 'Vowel Harmony 2'