As in many other Uralic languages, Erzya has vowel harmony. Most roots contain either front vowels (, ) or back vowels (, ). In addition, all suffixes with mid vowels have two forms: the form to be used is determined by the final syllable of the stem. The low vowel (), found in the comparative case -шка ("ška") "the size of" and the prolative -ка/-га/-ва ("ka"/"ga"/"va") "spatial multipoint used with verbs of motion as well as position" is a back vowel and not subject to vowel harmony.