ABSTRACT

Sino-Tibetan began as a single language but under the gentle push of language internal pressures and the far more intense infl uence of contact with other languages, it changed, repeatedly splitting and restructuring on the way to becoming the modern Sino-Tibetan language family. Little of this linguistic history is retained in even the earliest written records, but the broad outlines of the ebb and fl ow in the prehistory of the Sino-Tibetan languages and the peoples who spoke various versions of it are recoverable through the techniques of comparative reconstruction. Much of the relevant work, however, remains to be done. In particular, there are critical gaps in our understanding of Sino-Tibetan subgrouping-how the original language split up over time and who the speakers came in contact with. Accurate subgrouping is needed to distinguish between splits in the phylogenetic subgroups based on shared innovations-typically having as their nonlinguistic counterpart abrupt migrations, the dialect chains-areas in which a language has spread out and subsequently differentiated into separate languages, the linguistic areasareas with typological similarities brought about by language contact, and straight-out borrowings. Much of the Sino-Tibetan subgrouping is impressionistic or geographic, some of it presenting little or no actual supporting evidence. For the most part, this chapter provides a preliminary sketch of the subgroups for which some compelling evidence has been brought forth, however, because they are often mentioned in the literature, it also discusses some subgroupings which seem to lack any serious supporting evidence. 2,3

1.1 Phylogenetic ‘trees’ versus linguistic areas

For phylogenetic subgrouping, the standard assumptions about subgrouping need stating: only linguistic data constitutes evidence for a linguistic subgrouping-not geography, not ethnography, not folklore. Of course, if the resulting subgrouping is at variance with known history, for instance, either or both should be carefully re-examined. Only the shared innovations among the correspondence sets constitute evidence of an earlier period of common development; as a corollary, the value of an innovation for subgrouping varies inversely with the probability that it could have happened more than once independently-the less likely that it could have happened independently, the more valuable it is as a subgrouping tool.