Durational variations in Oromo vowels

Abstract

An acoustic study of vowels of Cushitic languages has not been undertaken, though their vowels seem to exhibit durational variations. We wanted to identify factors that would affect vowel length in Oromo, a Cushitic language widely spoken in the Horn of Africa. Sixty-four speakers (F = 32, M = 32) from four dialect areas of the language in Ethiopia produced vowel data in different environments. An acoustic analysis of the data showed that duration of the vowels varies significantly across dialects, with the longest duration in the Eastern dialect and the shortest duration in the Western dialect. Gender has no significant effect on duration of the vowels, but the vowels have significantly longer duration when followed by voiced singletons than voiceless, and when followed by voiced singletons than by voiced geminates. Collectively, phonologically long vowels are two times longer than short ones, and this difference is significantly affected by dialect and environment, but not by gender. A significant variation was also observed among the vowels with regard to their intrinsic duration. It is concluded that, besides phonological length, the regional background of speakers and phonetic environment are key factors determining duration of Oromo vowels.