The Lowland Kenyah posterior implosives

The Kenyah languages of central Borneo form a distinct unit within the North Sarawak group of Austronesian languages. In northern Sarawak there is a well-defined contrast between types that have been called ‘Highland Kenyah’ and ‘Lowland Kenyah’. A key difference between these sets of closely-related languages is the reflexes of Proto-North Sarawak/Proto-Kenyah *b, *d, *j, *g and *b^h, *d^h, *j^h, *g^h, which are distinguished (usually as b, d, j, g vs. p, t, c, k) in Highland Kenyah, but show a complex set of innovations in some varieties of Lowland Kenyah. The most striking of these changes in the dialect spoken by the Lebu’ Vu’ Kenyah at Long Sela’an and Long Ikang, and the Long Tikan Kenyah at Long San, is the shift of voiced aspirates to phonetic implosives that were generalized to the reflexes of *b, *d, *j, *g as final syllable onsets, leading to merger of the two series. Because it was conditioned, this merger produced complementation between [b]/[ɓ], [ɟ]/[ʄ], and [g]/[ɠ] (*d lenited before implosion was generalized, preventing merger). Most remarkably, the reduction of Proto-Kenyah nasal-obstruent clusters in these dialects has begun to produce new instances of [ɟ] and [g], but not [b] and [d], creating contrastive implosives only at palatal and velar positions, a reversal of the distributional preference commonly associated with implosive stops in cross-linguistic perspective.