Proto-Mayan is the hypothetical common ancestor of the 30 living Mayan languages, as well as the Classic Maya language documented in the Maya inscriptions. While there has been some controversy with Mayan subgrouping, there has been a general agreement that the following are the main five subgroups of the family: Huastecan, Yucatecan, Cholan-Tzeltalan, Kanjobalan-Chujean, and Quichean-Mamean.
The Proto-Mayan language is reconstructed (Campbell and Kaufman 1985) as having the following sounds:
It is unlikely the language had a tonal system.
The following set of sound changes from proto-Mayan to the modern languages are used as the basis of the classification of the Mayan languages. Each sound change may be shared by a number of languages; a grey background indicates no change.
The palatalized plosives and have not been retained in most of the modern languages, a notable exception being the Ch'ol language. Instead they are reflected differently in different branches allowing a reconstruction of these phonemes as palatalized plosives. In the western branch (ChujeanâÂÂQüanjobüalan and Cholan) they are reflected as and . In Mamean they are reflected as and and in Yukatek and Küichean as and .
The Proto-Mayan liquid is reflected as in the western languages (ChujeanâÂÂQüanjobüalan and Cholan), Huastecan and Yukatek but as in Mamean and in Küichean and Poqom.
Proto-Mayan velar nasal is reflected as in the eastern branches (KüicheanâÂÂMamean), as in Qüanjobüalan, Cholan and Yukatekan, and only conserved as in Chuj and PoptÃÂ. In Huastecan is reflected as .
The changes of Proto-Mayan glottal fricative are many and it has different reflexes according to position. In some positions it has added length to the preceding vowel in languages that preserve a length distinction. In other languages it has the reflexes , , , or a zero-reflex.
Only KüicheanâÂÂMamean and some Qüanjobüalan languages have retained Proto-Mayan uvular stops and whereas all other branches have changed these into and respectively.
In Mamean a chain shift took place changing into , into , into and into . These retroflex affricates and fricatives later diffused into Qüanjobüalan.
In polysyllabic words Kaqchikel and Tzüutujil have changed a final Proto-Mayan and into and respectively.
Huastecan is the only branch to have changed Proto-Mayan into . Wastek also is the only Mayan language to have a phonemic labialized velar phoneme , but this is known to be a postcolonial development. Comparing colonial documents in Wastek to modern Wastek it can be seen that they were originally clusters of and a rounded vowel followed by a glide. For example, the word for "vulture" which in modern Wastek is pronounced was written <nowiki><cuyx></nowiki> in colonial Wastek and pronounced .
The Yucatecan languages have all shifted Proto-Mayan into in wordfinal position.
Several languages particularly Cholan and Yucatecan have changed short into .
All Cholan languages have changed long proto-Mayan vowels and into and respectively.
Vowel length distinction has been lost in Qüanjobüalan-Chujean (except for Mochoü 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 .