Aso, Reiko. Hateruma (Yaeyama Ryukyuan). 2010. hh:s:Aso:Hateruma
"One of the striking features of Hateruma is the strong aspiration of the word-initial consonants /p, t, d, k, g, f, s/. All voiceless obstruents except /c/ and /h/ can devoice a following vowel when they are aspirated; in addition, this devoicing can also spread to a subsequent sonorant." Maybe these are [dtʰ gkʰ]...? Unclear.