Vowel harmony is a phonological process which determines what vowel will appear in all but the first syllable of a word. In roots with more than one syllable, the second vowel harmonizes with the first one. Vowel harmony in Turkish is a combination of two kinds of harmonization process. One of these is fronting harmony, which is the assimilation of a vowel with the vowel in the preceding syllable in terms of frontness. The other type of harmony process is rounding harmony, which is the assimilation of a vowel with the vowel in the preceding syllable in terms of roundedness. In terms of vowel harmony, there are two types of suffix in Turkish, I-type and A-type. The vowels of I-type suffixes are high, but they get their other features from the preceding vowel. The vowels of A-type suffixes are unrounded and non-high, but are variable in terms of whether they are back or front.