Articulatory mapping of Yoruba vowels: an ultrasound study

Abstract

This paper examines the articulation of harmonically distinct classes of vowels in Standard Yoruba. There has been considerable disagreement as to whether the distinction between [e o] and [∊ ɔ] is one of vowel height or tongue-root advancement/retraction. This paper reports on an ultrasound investigation of Yoruba vowels. Results are consistent with harmonic classes distinguished by a tongue-root advancement/retraction feature, not by vowel height. We also investigate the relation between articulations of the tongue root and its neutral position between utterances, the inter-speech posture (ISP). We find more variability in ISP-to-articulation mapping than previous studies, but our results are still partially compatible with a postulated correlation between phonologically ‘active’ feature values and articulatory displacement from ISP. Overall, our results support an analysis of Yoruba vowels in terms of a tongue-root feature, and provide insight into the mapping between phonetics and phonology.