Articulatory and acoustic correlates of tongue root contrasts in Gua

Abstract

Vowel systems in West African languages are often noted for using the position of the tongue root (TR) to contrast vowels throughout the vowel space. E.g. X-ray studies of Igbo show that pairs of vowels such as /i/ and /ɪ/ contrast with regards to tongue root position. A similar study of Akan shows that vowel height also gets incorporated into the contrast (Ladefoged and Maddieson 1990). While many languages are noted for having TR contrasts, imaging data are available for only a small subset. Gua, a Kwa language from the Niger Congo family spoken in coastal Ghana (Simons and Fennig 2017, Yeboah-Obiri 2013), is a critically under-documented language which contains TR contrasts in all high and mid vowels (Advanced TR: /i e o u/; Retracted TR: /ɪ ɛ a ɔ ʊ/). Acoustic analysis and articulatory data from 3D ultrasound recordings reveal that RTR vowels show a variety of deformations of the tongue surface, depending on the vowel. However, these deformations are linked by the mechanics of tongue root retraction. Also, images reveal that differences in tongue height in addition to TR advancement are often present.