In the Indonesian literature discussing the various peoples inhabiting Jambi Province in Sumatra, a taxonomy is frequently given:

Weddoid Kubu

Proto-Malay Bajau
Kerinci
Batin

Deutero-Malay Jambi Malay
Penghulu
Pindah
(Yunus 1986)

Given the virtual non-existence of written sources documenting the early history of Sumatra, we have to look elsewhere for input into this "two-wave" migration theory. Leading archaeologists, for example, using the tools of their trade have concluded that there is scant archaeological basis for a Proto-/Deutero-Malay split. Linguistics is another discipline that could shed light on the question. However, until the present, there have been no published linguistic descriptions of the so-called Batin, Pindah or Penghulu speech varieties of upstream Jambi (although other Malay areas of Sumatra are better documented). Based on the findings of recently-completed dialect survey conducted among Malay speakers in downstream and upstream Jambi, this paper employs the techniques of historical linguistics to examine evidence for the purported Proto- and Deutero-Malay waves of settlement in Jambi. It first lays out what type of linguistic evidence should exist if this theory is true, and then shows that no such evidence is forthcoming. Instead of evidence for a Proto-Malay/Deutero-Malay split, it is shown that these varieties are closely related and stand squarely in the Malay camp. For example, Jambi Malay Ulu (JMU or "Batin") varieties can be shown to have descended from Proto-Malayic using Adelaar's (1992) set of eleven developments. Moreover, this cluster of varieties fits somewhere halfway between Standard Malay and Minangkabau in terms of sound changes from Proto-Malayic, and both of the latter have been shown to be equal members of the Malayic family (Adelaar 1992, 1995). Moving beyond polemics, the paper seeks to locate JMU linguistically within a central Sumatran Malay dialect network and to identify a few of its potential contributions to a fuller understanding of areal historical development, particularly Minangkabau-type phonological changes. The question of whether there is such a thing as the "Suku Batin" language (e.g. Grimes 2000) is also taken up and if not, what sort of meaningful dialect boundaries can we draw.