If we repeat the line in red from the last paragraph in the previous section:
A suffix is by definition one or more “subsequent” syllables (suffix = subsequent).
In Turkish the first vowel of a suffix will be one of the following:
- fixed: form (1),
- an “a/e” depending on the previous vowel and the vowel harmony rules: form (2),
- an “i/ı/ü/u depending on the previous vowel and the vowel harmony rules: form (4).
Most Turkish verbs, prepositions and pronouns come as suffixes. The suffixes are appended in a certain order to the stem. The stem is a noun, verb or adjective, and the suffix typically corresponds typically to an English preposition, state of a name, a verb tense, a person (I/you/..) etc.
A minority of suffixes are (always or alternatively) written as separate words, but they behave, ie they are declined, just like a suffix which is attached to the previous word.
The vowels in a suffix change depending on the last vowel in front of it: yan+dı (burned), yen+di (won).
Consonant harmony: If the suffix starts with a consonant and the letter in front of it is also a constant, the first letter of the consonant or sometimes the last letter in front of it may change, to match each other. This makes it physically easier to speak the word.
Suffixes come in sets of 1, 2, or 4, which we will call: the form (1), form (2), and form (4).
Vowel harmony: Throughout this guide, when a (1), (2) or (4) is given after a suffix, it shows the form of the suffix. When it is form (2) or (4), you will need to use the second rule of harmony to pick the matching form of the suffix. When it is form (1), the vowels in the suffix does not change regardless of the vowel in front of it.
Note that every suffix of form (1) is automatically an exception to the first rule of vowel harmony, because the first vowel of the suffix will conflict with the preceding vowel according to the two rules of harmony. This exception typically comes from the fact that these suffixes were originally separate words.