Mixe phonology is complicated and little documented. There is a palatalized series of all consonant phonemes (as in Russian, Polish, or Gaelic) and possibly a fortis/lenis distinction in the stop series, the recognition of which however is obscured by a tendency of allophonic voicing of consonants in voiced environments. Syllable nuclei are notoriously complex in Mixe, varying in length and phonation. Most descriptions report three contrastive vowel lengths. There are multiple values of phonation, one being the typical one (what some phoneticians call "modal voicing"). The other types of phonation have been variously termed checked vowels, creaky voice vowels and breathy voice vowels. Some Mixe variants are vowel innovative and some, notably North Highland Mixe, have complicated umlaut systems raising vowel qualities in certain phonological environments.
| Bilabial | Dental/ Alveolar |
Post- alveolar |
Palatal | Velar | Glottal | ||
|---|---|---|---|---|---|---|---|
| Plosive | voiceless | p /p/ | t /t̪/ | c /c/ | k /k/ | q /ʔ/ | |
| voiced | b /b/ | d /d̪/ | j /ɟ/ | g /ɡ/ | |||
| Fricative | voiceless | f /ɸ/ | þ /θ/ | s /ʃ/ | ĉ /ç/ | x /x/ | h /h/ |
| voiced | v /β/ | ð /ð/ | z /ʒ/ | ĵ /ʝ/ | ɣ /ɣ/ | ħ /ɦ/ | |
| Affricate | voiceless | ť /ts/ | š /tʃ/ | ||||
| voiced | ď /dz/ | ž /dʒ/ | |||||
| Nasal | m /m/ | n /n̪/ | ɲ /ɲ/ | ŋ /ŋ/ | |||
| Approximant | w /w/ | r /j/ | l /ʟ/ | ||||
| Front | Central | Back | ||
|---|---|---|---|---|
| Close | y /i/ | ə /ɨ/ | u /u/ | |
| Near-close | i /ɪ/ | ʊ /ʊ/ | ||
| Mid | unrounded | e /e/ | ɛ /ɜ/ | ʌ /ɤ/ |
| rounded | ø /ø/ | ɵ /ɞ/ | ɔ /o/ | |
| Open-mid | ë /ɛ/ | ö /ʌ/ | ||
| Open | æ /æ/ | a /a/ | o /ɒ/ | |
The three vowels (/a, o, u/) resulting in a suprasegmental palatalization then range to three vowel qualities ([æ, ø, ʊ]).