Donohue, Mark; San Roque, Lila. I'saka: a sketch grammar of a language of north-central New Guinea. 2004. hh:g:DonohueSanRoque:Isaka
Tone is word-level. Disyllabic tone patterns are HL, LL, LH, LR, RH, RL. In monosyllables:
- HL > F
- LL > L
- LH > R
- LR > R
- RH > H
- RL > F
Vowels have weak nasalization after /b d/ [m n] and strong nasalization following any other onset, including zero.
Initial clusters are /pd bd td sd/; these are only allowed in monosyllables. /l p/ are found in coda position only rarely, and there's one instance of coda /s/. (Coda /l p s/ were probably introduced by loans.) Otherwise, syllable structure is (C)V(j w).
Initial clusters can't appear in nasal syllables.