Consonant Phonemes
| Labial | Dental | Alveolar | Velar | Glottal | |
| Nasal | m | n | ŋ | ||
| Stop | p b | t d | k g | ||
| Fricative | f v | θ ð | s z | h | |
| Approximant | w | l̥ l | j | ||
| Trill | r̥ r |
- Obstruents undergo word-final devoicing.
- Velar plosives /k, g/ surface as [h] in syllable final position.
- Velar consonants are palatalized when followed by a front vowel.
- Alveolar plosives /t, d/ surface as [s, z] in syllable final position.
- /s/ is deleted in word-final position.
- /l/ is vocalized in word-final position as [u].
- Nasals undergo place assimilation in syllable-final positions. In word-final position, they surface as [ŋ] when preceded by a front vowel, as [m] when preceded by /u/, and elsewhere as [n].
- [g] is inserted after /ŋ/ in intervocalic positions and /ŋ/ becomes the coda of the preceding syllable.
Vowel Phonemes
| Front | Back | |
| High | i | u |
| Mid-High | e | o |
| Mid-Low | ɛ | |
| Low | æ | ɑ |
- The vowels /æ/ and /e/ can be analyzed as allophones as they occur in complementary and predictable phonetic contexts. /æ/ occurs in closed syllables or unstressed, open syllables and is often short, while /e/ occurs in stressed and word-final, open syllables and is often a long vowel.
- /i/ is deleted in unstressed syllables through the addition of another vowel when the preceding consonant is /l/ or /r/ and following consonant is an obstruent or nasal.
- Disyllabic /a.u/ collapse to monosyllabic [o] in a closed a syllable followed by one or more syllables.
- The vowel /e/ and sometimes vowel /æ/ are alternatively pronounced as the diphthong [ae], especially in poetry or when using a more archaic pronunciation.
Stress and Syllable Structure
The basic syllable structure of Lisadian is C(C)V(C). The secondary onset can only be /w/ and can only occur on stressed syllables. Codas are limited to sonorants and fricatives.
Stress in Lisadian is non-phonemic, and the primary stress always falls on the third-to-last, or antepenultimate syllable. Secondary stress is usually added to every third preceding syllable.