Labial Harmony occurs when an unrounded vowel in the first syllable is followed by unrounded vowels or when a rounded vowel in the first syllable is followed by narrow rounded or unrounded wide vowels. Labial Harmony doesn't have the tendency of levelling in the periods of Turkish language and its other areas. Although there was general labial harmony apart from exceptions in the old Turkish period, this harmony was destroyed and it was nearly disappeared in old Oghuz Turkish. In this period, some affixations were permanently unrounded or some of them were permanently rounded. After The Oghuz Turkish period, there was no complete labial harmony in most part of The Ottoman Turkish. Labial Harmony was enabled systematically in the period of passing from Oghuz Turkish to Turkey Turkish, that is, in the late Ottoman Turkish.