Obstruent devoicing and registrogenesis in Chru

We describe the register system of Chru, a Chamic language of Vietnam. In Chru, a historical contrast between prevoiced and voiceless stops is now a system of two registers signalled by differences in f0, voice quality, and F1 in addition to closure voicing. However, closure voicing is in a state of flux: while older men maintain closure voicing in the onsets of low-register items, younger speakers and some older women frequently have no (or only weak) closure voicing in this context. In addition, the distribution of VOT in low register onsets is bimodal, realized either with strong closure voicing or greater VOT than voiceless stops. Interestingly, f0, F1 and voice quality cues are not enhanced after devoiced low-register stops, but instead are more pronounced after stops realized with closure voicing. We argue this indicates that enhancement of cues in phonologization must in some sense be complete before neutralization takes place.