Phonology
One characteristic feature of Sakha is vowel harmony. For example, if the first vowel of a Sakha word is a front vowel, the second and other vowels of the same word are usually the same vowel or another front vowel: кэлин (kelin) "back": э (e) is open unrounded front, и (i) is close unrounded front.
Read more about this topic: Yakut Language