Blust (1969) recognized a North Sarawak subgroup of Austronesian languages based on a single highly distinctive sound change, namely the split of Proto-Austronesian *b, *d/j, *z, and *g into a "plain" series of voiced obstruents, and another characterized as "phonetically complex." This second series includes implosives, the first true voiced aspirates ever reported, and unexpected developments such as *b > (*bh) > s. A claim that the North Sarawak languages form part of a larger North Borneo group that includes the indigenous languages of Sabah has been in circulation since Blust (1974b), and was further elaborated in Blust (1998). Despite this claim, both the North Sarawak and North Borneo hypotheses have received scant attention in broader discussions of Austronesian subgrouping, which sometimes stress the absence of well-established large subgroups in western Indonesia (Ross 1995:72). A number of proposed lexical innovations suggest that North Borneo is part of a still larger group that incorporates Malayo-Chamic, Moken, Rejang, Sundanese, and all other languages of Borneo except the Barito family. This wider group, which notably excludes Madurese, Balinese, and Sasak, is called "Greater North Borneo." Although it is not the primary focus of this paper, there is additional evidence that Greater North Borneo forms part of a more encompassing "Western Indonesian" subgroup that includes all Austronesian languages of mainland Southeast Asia, Madagascar, and the Greater Sunda Islands, but not the languages of Sulawesi.