Boiken language

Boiken (Nucum, Yangoru) is one of the more populous of the Ndu languages of Sepik River region of northern Papua New Guinea. It is spoken around Boiken Creek in Yangoru-Saussia District, East Sepik Province and adjacent islands off the north coast of northern Papua New Guinea.^[1]

Phonology

Boiken consonants^[2]
		Labial	Dental	Alveolar	Dorsal	Glottal
Nasal		m	n̪	n	(ŋ)
Stop		p		t	k	(ʔ)
Affricate			t̪s̪
Fricative	voiceless	ɸ		s	x
Fricative	voiced				ɣ
Approximant		w	l̪		j
Trill				r
Flap				ɺ

Stop sounds /p, t̪s̪, t, k/ are heard as voiced [b, d̪z̪, d, ɡ] when following a nasal counterpart.
/k/ has an allophone of a glottal [ʔ] in word-final position, or when preceding a consonant in word-medial position.
Sounds /ɸ, s, x/ can be voiced as [β, z, ɣ] in intervocalic positions.
/n/ is heard as [ŋ] when preceding velar consonants, or freely in word-final position.
/r/ can be heard as a voiceless trill [r̥] in word-initial positions.

/ɨ, ə/ have allophones of [ɪ, ɛ] when following dental and alveolar sounds.
/u/ has an allophone of [ʊ] when preceding /k/ heard as a glottal [ʔ] in word-medial and word-final positions.
/o/ has an allophone of [ɔ] when following labial and velar sounds.

^ e25
^ Freudenburg, Allen & Marlene (1974). Boiken phonemes. In Richard Loving (ed.), Phonologies of four Papua New Guinea languages: Ukarumpa: Summer Institute of Linguistics. pp. 97–127.

Paradisec houses two collections of Arthur Capell's materials that include Boiken (AC1 and AC2) as well as notes from Don Laycock's work (DL2) all of these collections are open access.