(Jump up one level to Enemish)
Proto-Walu-Siwaish (pWS) speakers occupied the south-western plain of Taiwan shortly before 4500 BP. The breakup of pWS produced three groups. One: western Walu-Siwaish, remained in the southwestern plains, ultimately splitting into Hoanya and Papora; a second group—central Walu-Siwaish—moved north into mountain territory in the Formosan interior; while a third group—eastern Walu-Siwaish— crossed the southern extremity of the central mountain range, introducing the neolithic way of life to the East coast c. 4500 BP (Hung 2008:71-73). All modern east-coast languages, plus Malayo-Polynesian and Kra-Dai languages belong to this last clade.
Walu-Siwaish language are characterized by the appearance of the ‘modern’ numerals for ‘8’ and ‘9’: *walu and *Siwa respectively, as well as of their several variants. For ‘8’: *bahlu, *balu, and *halu; for ‘9’, *siba (Sagart 2004; 2014). Similar forms cannot be found further north on the west coast, except in long shapes like Pazeh xasepatelu ‘8’, xasepisupat ‘9’, which reveal their etymologies as ‘5+3’ and ‘5+4’ (Sagart 2004).
Hung, Hsiao-chun. 2008. Migration and Cultural Interaction in Southern Coastal China, Taiwan and the Northern Philippines, 3000 BC to AD 100: The Early History of the Austronesian-speaking Populations. Unpublished PhD dissertation, Canberra: the Australian National University.
Sagart, Laurent. 2004. The higher phylogeny of Austronesian and the position of Tai-Kadai. Oceanic Linguistics 43,2: 411-444.
Sagart, Laurent. 2014. In Defense of the Numeral-based Model of Austronesian Phylogeny, and of Tsouic. Language and Linguistics 15(6) 859–882.