Uvular Reflexes of Proto-Austronesian *q: Mysterious Disappearance or Drift Toward Oblivion?

This paper demonstrates an unexplained typological oddity in the historical phonology of Proto-Austronesian: PAN *q, widely believed to be a voiceless uvular stop, is rarely continued as a uvular consonant outside of the Formosan languages. The rarity of uvular reflexes of PAN *q in Austronesian languages is striking: of the 1,000 or so non-Formosan Austronesian languages, only two, Muna and Mapos Buang, show possible uvular reflexes of *q while maintaining an inherited contrast between that segment and reflexes of *k. If PAN *q was a uvular stop, and maintained as such in Proto-MalayoPolynesian, Proto-Central/Eastern Malayo-Polynesian, Proto-Central MalayoPolynesian, Proto-Eastern-Malayo-Polynesian, Proto-South Halmahera–West New Guinea, and Proto-Oceanic, why are there so few Austronesian languages outside of Taiwan with uvular reflexes of *q? Several possible explanations are considered here, ranging from simple typological explanations to cultural factors related to sound symbolism and taboo. The most promising approach relates drift away from *q to expansion of the vowel inventory.