Lingual articulation of the sūzhōu chinese labial fricative vowels

In this paper, we describe lingual activity for three back vowels with different labial constrictions in Suzhou Chinese: a rounded high back vowel [u] and twomore unusual vowels, vertically compressed [ɯβ] and labiodental [ɯv]. The latter two vowels are so-called fricative vowels, consistently produced with slight fricative noise; [ɯβ] also sporadically exhibits bilabial trilling. Smoothing-spline ANOVA models of tongue surface contours extracted from ultrasound recordings suggest that [ɯβ] and [ɯv] have a tongue position lower and fronter than [u]. Linear mixed effects modeling of contour shape parameters also suggests that [u] has a less flat and more complex, back-raised tongue shape than [ɯβ] and [ɯv]. We relate the lowered tongue body of [ɯβ] and [ɯv] to the trading relations between lingual and labial activity that characterize rounded vowels, as well as to aeroacoustic properties of labial fricatives and bilabial trills.