An acoustic analysis of Oromo vowels of the northern dialect

Abstract

This study presents the results of an acoustic analysis of Oromo vowels of the northern dialect. The data for the study were collected from 19 speakers (nine female, 10 male) who produced the vowels in the same phonetic environment. Such acoustic measures as duration, fundamental frequency and the first three formant frequencies were extracted for the analysis. In a linear mixed-effects model, each acoustic parameter was modelled as a function of the fixed effects such as gender and vowel quality, and of participants’ random effects. The model shows a main effect of gender on all the acoustic measures, with the female speakers producing the vowels with significantly greater duration and formant frequencies. The model also indicates the main effect of vowel quality on all the acoustic measures with the exception of duration. The proportion of variances explained by gender and vowel quality is found to be large for fundamental frequency and the first formant frequency respectively. As regards the classification of the vowels, Support Vector Machine reveals that the time-varying frequency does not have an advantage over a steady state in separating vowels of both genders. However, it is generally fairly effective in classifying vowels of the dialect of the language.