Low-vowel fronting in northern Sarawak

A number of the languages of northern Sarawak have fronted earlier *a under theoretically challenging conditions. In general, *a has been fronted foll owing a voiced obstruent, subject to various qualifications that are noted in individual languages. This type of change bears a superficial resemblanc e to vowel raising following breathy voiced consonants in many of the Mon-K hmer languages of mainland Southeast Asia. However, caution should be obser ved in comparing the two situations because: (1) the evidence strongly sugg ests that although both fronting and raising are involved, raising is an in cidental by-product of vowel fronting in the languages of northern Sarawak, (2) breathy voice is a prosody that spreads rightward until interrupted by certain consonants; in words of the form *CaCaC, however, fronting may ski p the first low vowel and target the more distant one, (3) none of the lang uages in question has ever been reported as having breathy consonants. Fina lly, although all but one of the nine languages used to illustrate this phe nomenon are members of a linguistic subgroup, "Berawan-Lower Baram," differ ences of detail in the conditioning of vowel fronting suggest that the chan ge was not present in their immediate common ancestor, but was acquired ind ependently in some or all of the languages, a conclusion supported by the d iscovery of similar changes outside northern Sarawak.