San-gwo Thum

Consonants

 * The phonemes /l/ and /ɾ/ are considered allophones

Vowels
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 * The phoneme / ɻ/ is recognised both as a consonant and a vowel

Tones
There are 9 basic tones in San-gwo Thum: Each vowel must carry one of these tones. Syllables may also have compound tones, in which any of the two tones may be combined, provided that the end point of the first tone is the same as the start point of the second, and that they do not travel in the same direction (e.g. low rising + high rising). These may be carried by either lone vowels or diphthongs. This gives a total of 31 possible tones altogether.
 * Still tones: Low (˩), Middle (˧), and High (˥)
 * Rising tones: Low (˩˧), High (˧˥), and Low-high (˩˥)
 * Falling tones: High (˥˧), Low (˧˩), and High-low (˥˩)

Phonotactics
The syllable structure of San-gwo Thum is (C₁)(C₂)V(V)(C), in which  C₁ is any non-approximant consonant and  C₂ is any approximant consonant. In  (C₁)(C₂)VC syllables, single, non- / ɻ/  vowels carrying only a basic tone become shortened, if the final consonant is not /n/. The vowels of syllables that end with /n/ become nasalised, with the /n/ not being pronounced. Voiced plosive consonants are not released at the ends of syllables.