Alamblak is spoken along the Wagupmeri and
Karawari rivers, E. Sepik province, Papua New Guinea.
Palato-alveolar consonants often arise from blending of an
alveolar + preceding or following /j/. Nonsibilant
fricatives are voiced between voiced segments, except when
a nasal precedes. An analysis of the vowel system as
containing only 3 central vowels, with front and back
variants conditioned by adjacent approximants /j/, /w/ is
discussed by Bruce (1984). However there are several
problems with this analysis, e.g. [i] from abstract high
central vowel + /j/ would be expected to palatalize a
following /t/ but doesn't.

Bruce, Les. 1984. The Alamblak Language of Papua New
Guinea (East Sepik). Pacific Linguistics, series C no. 81.
Australian National University, Canberra.