There have been plenty of publications (mostly by David Gil) discussing how Riau Indonesian is a unique language that lacks word categories.
To me, this sounds huge: a truly unique language, no word classes, limits of languages broadened. I'm no linguist, but I think if I were, I would certainly want to learn more about it.
Yet it's been suspiciously quiet on this matter recently. No new publications, no further reasearch - other than D. Gil, no-one even seems to care about it.
My question is: is Riau Indonesian even genuine as a monocategorial language? Or was it (perhaps) a mistake made by Gil? And if it is genuine, why does it get so little attention?