Bwaidoka language
Bwaidoka is an Austronesian language spoken in Milne Bay Province of Papua New Guinea. It is a local lingua franca.

Phonology

Consonants 

  can be pronounced as alveolar , or dental  when preceding central or back vowels.
  can be pronounced as a voiced plosive , or as a fricative  on an unstressed syllable.
  can be pronounced as either  or as  in free variation.

Vowels 

 Vowel sounds  do not occur following labialized consonants.
  may fluctuate freely from  to  in syllable-final, and with  as the first vowel sound on stressed syllables.
  may fluctuate freely from  to  on unstressed syllables and as the second vowel sound on stressed syllables.
  may fluctuate freely from  to  on unstressed syllables and as the second vowel sound on stressed syllables.

References 

Nuclear Papuan Tip languages
Languages of Milne Bay Province