8th Annual Conference of the International Speech Communication Association

Antwerp, Belgium
August 27-31, 2007

An Articulatory and Acoustic Study of "Retroflex" and "Bunched" American English Rhotic Sound Based on MRI

Xinhui Zhou (1), Carol Y. Espy-Wilson (1), Mark Tiede (2), Suzanne Boyce (3)

(1) University of Maryland, USA
(2) MIT, USA
(3) University of Cincinnati, USA

The North American rhotic liquid has two maximally distinct articulatory variants, the classic "retroflex" and the classic "bunched" tongue postures. The evidence for acoustic differences between these two variants is reexamined using magnetic resonance images of the vocal tract in this study. Two subjects with similar vocal tract dimensions but different tongue postures for sustained /r/ are used. It is shown that these two variants have similar patterns of F1-F3 and zero frequencies. However, the "retroflex" variant has a larger difference between F4 and F5 than the "bunched" one (around 1400 Hz vs. around 700 Hz). This difference can be explained by the geometry differences between these two variants, in particular, the shorter and more forward palatal constriction of the "retroflex" /r/ and the sharper transition between palatal constriction and its anterior and posterior cavities. This formant pattern difference is confirmed by measurement from acoustic data of several additional subjects.

Full Paper

Bibliographic reference.  Zhou, Xinhui / Espy-Wilson, Carol Y. / Tiede, Mark / Boyce, Suzanne (2007): "An articulatory and acoustic study of "retroflex" and "bunched" american English rhotic sound based on MRI", In INTERSPEECH-2007, 54-57.