Which Uralic languages have forms of vowel harmony?

Vowel harmony is a linguistic feature found in several Uralic languages, though its presence and productivity vary across the family.

• Finnish and Hungarian: These languages exhibit productive and active systems of vowel harmony, where vowels within a word must generally agree in terms of frontness or backness.12
• Other Languages: Similar, though less general, front-back vowel harmony systems are found in specific dialects of Mordvin, Mari, Mansi, Khanty, and Kamas.1

It is important to note that not all Uralic languages possess this feature. For instance, Estonian and Livonian, along with Sami, have lost or do not exhibit vowel harmony. Scholars often attribute the presence of vowel harmony in many Uralic languages to areal influence—particularly from neighboring Turkic languages—rather than a shared genetic origin from Proto-Uralic.13