Proto-Maritime is reconstructed as having twenty-one phonemes. It was characterised by three points of vowel articulation, a lack of contrastive voice and the prominence of velar, uvular and glottal sounds. Syllables were simple or moderately complex.
The standard model of PM phonology has stood the test of time, but some uncertainties remain. The language was unwritten. It is believed that there were two dialects, one spoken in what is now Kuna, one in what is now Tepi. Little is known about them, however.
PM had six monophthongs, three short and three long. Long vowels are written double in this transcription.
The International Phonetic Alphabet is used here to indicate typical values. No doubt the sounds of each vowel varied widely in practice but few of the details of vowel variation are known.
High vowels were lowered to mid-high position when adjacent to uvular consonants q, nq. So i would then be pronounced /e/ and u would become /o/. Their long counterparts would become /e:/ or /o:/ respectively.
The central vowel a became a back vowel /ɑ/ when adjacent to a uvular.
Changes around uvulars still seem to have occurred across word boundaries.
All short vowels were somewhat centralised when unstressed in closed syllables. In those positions, they became /ɐ, ɪ, ʊ/ respectively.
The combination of any short monophthong with a reduced i or u was a valid diphthong in PM. A always kept its full sound. At this stage, it is not possible to tell which vowel reduced in the diphthongs iu and ui.
The language does not appear to have possessed any triphthongs.
PM had a set of fifteen consonants. These included balanced sets of stops and sonorants and a few fricatives.
Any consonant could be geminated apart from y and w. Geminates are written double in this transcription: kk, etc. The trigraphs ngg and nqq represent geminate /ŋ/ and /ɴ/ respectively.
Unlike in English, stops were never aspirated and r was always trilled.
The uvular nasal is transcribed here as nq for reasons of convenience and aesthetics. It is, nonetheless, a voiced sound like all the other PM nasals.
Velar consonants became uvular before uvulars and vice-versa. This is reflected in the transcription except across word boundaries. Thus k+q became qq and q+k became kk, etc.
Labial and alveolar consonants were deleted before uvulars and the uvular geminated. For example, t+q became qq.
Nasals were homorganic with the following consonant.
S was in free variation between laminal and apical varieties. The first of these sounds was more hissing, the second more hushing.
H became /x/ in syllable-final position.
L became /ʟ/ in syllable coda position.
Only the following syllable types were permitted in Proto-Maritime:
Any consonant could appear in onset position. Any could appear in coda apart from y and w.
Syllables were classed as light: V, CV or heavy: VC, CVC, VV, CVV, VVC, CVVC.
Stress normally fell on the penultimate syllable. However, if the final syllable was heavier, it took the stress instead. Secondary stress occurred on every alternate syllable before the one with the primary stress.