長母音
Vowel length distinction has been lost in Qʼanjobʼalan-Chujean (except for Mochoʼ and Akateko), Kaqchikel and Cholan. Some languages have reduced the vowel length distinction into a tense lax distinction that was later lost for most vowels, Kaqchikel however retains a centralized lax schwa-like vowel as a reflex of Proto-Mayan . Two languages, Yukatek and Uspantek and one dialect of Tzotzil have introduced a tone distinction in vowels between high and low tones as reflexes of former vowel length and and .