A preliminary ultrasonic investigation of tenseness in Northern Yi

This study investigates the articulatory and acoustic features of tense-lax vowel contrast in Northern Yi. Northern Yi has five pairs of phonologically-defined tense and lax vowels. Previous studies have shown that the difference between tense and lax vowels lies mainly in phonation type, while the vowel quality difference between the two types of vowels remains controversial. The current study provided tongue shape data and acoustic data of all tense and lax vowels in a Northern Yi dialect, Suondi Yi, using ultrasound imaging and acoustic analysis. The ultrasound data showed that tense vowels were consistently articulated with a more retracted tongue root and a lower tongue front compared to lax vowels. Acoustically, tense vowels have a higher F1 and a lower F2 compared to lax vowels. The data suggests that there are consistent vowel quality differences between all tense-lax vowel pairs in Northern Yi, and the vowel quality difference involves advanced tongue root/retracted tongue root ([ATR]/[RTR]) contrast.