Bugenhagen, Robert D.. Language change on Umboi island. 1994. hh:hvs:Bugenhagen:Umboi
"Word-finally, all obstruent manners are neutralised, with only the voiceless obstruents occurring. Morpheme-medially, the opposition between voiceless and voiced oral obstruents is almost completely neutralised, with the voiced versions surfacing when they are underlyingly intervocalic and voiceless versions surfacing when they are underlyingly preceded by a consonant. The only instances of contrast between medial voiceless and voiced oral obstruents are in a handful of loan words. Morpheme-initially, the contrast between the prenasalised stops and the voiced oral stops is partially neutralised. Prenasalised stops occur: 1) before voiceless stops, 2) before nasals, and 3) before /l/ or /r/, but never occur before an immediately following voiced oral stop or prenasalised stop in the same morpheme. Voiced oral stops, on the other hand, occur before voiceless obstruents, voiced oral obstruents, and /l/ or /r/. I have found only two instances of these morpheme-initial voiced oral stops being followed by nasals and no instances of their being followed by prenasalised stops. "