Dialects differ slightly in their phonology. Presented below are the vowel and consonant inventories of Mayrinax Atayal (Huang 2000a). Orthographic conventions are added in <angle brackets>.
Vowels[]
| Front | Central | Back | |
|---|---|---|---|
| High | i | u | |
| Mid-high | ɪ <ʌ> | ʊ | |
| Mid | e | ə | o |
| Mid-low | ɛ | ɔ | |
| Low | æ | a | ɒ <ø> |
Consonants[]
| Bilabial | Alveolar | Palato- alveolar |
Palatal | Velar | Uvular | Pharyngeal | Glottal | ||
|---|---|---|---|---|---|---|---|---|---|
| Stop | Voiceless | p | t | k | q | ʔ | |||
| Voiced | b | d | ɡ <j> | ɢ <ĵ> | |||||
| Affricate | ts <c> | tʃ <ç> | |||||||
| Fricative | Voiceless | ɸ <f> | s | ʃ | x | χ <ẋ> | ħ <h> | ||
| Voiced | β | z | ʒ | ɣ <g> | ʁ <ġ> | ||||
| Nasal | m | n | ŋ | ɴ <ɲ> | |||||
| Trill | ʙ <v> | r | ʀ <ř> | ||||||
| Semivowel | w | j <y> | ɰ <l> | ||||||
Most of these sounds are also encountered in other Formosan languages, but the velar fricative [x] is a trade mark of Atayalic languages. This sound has restricted distribution, though, as it never occurs in word-initial position.
Even though some literature includes a glottal fricative in the consonant inventory, that phoneme is phonetically realized as a pharyngeal (Li 1980), which is true for Atayalic languages in general. The alveolar fricative (s) and affricate (ts) are palatalized before [i] and [j], rendering [ɕ] and [tɕ], respectively (Lu 2005), as in the Sinitic contact languages Mandarin Chinese and Taiwanese Hokkien.
Plngawan Atayal (a subdialect of Ci'uli') differs from this inventory in that it lacks a schwa (ə), and that there are two phonemic rhotics (Shih 2008).
Squliq Atayal has a voiced alveo-palatal fricative [z] (Li 1980), but Huang 2015 doubts its phonemicity, arguing that it is an allophone of [y].