Vocal tract configurations in yodelling--prospective comparison of two Swiss yodeller and two non-yodeller subjects.

Yodelling consists of changes in pitch, presumably produced in different vocal registers. It is often assumed that vocal tract configuration is important to vocal registers and thus also to yodelling. We analysed vocal tract configuration in yodelling with dynamic real-time MRI (8 frames/second) in two (female and male) Swiss yodellers and two (female and male) professional classical singers. MR profiles showed clearly different vocal tract shapes for lower (vowel /[Formula: see text]/) and upper pitch (vowel /u/) for both the yodellers and the singers. These differences were similar for yodellers but differed between both classical singers. When switching to the upper pitch the yodellers decreased their lip opening with nearly constant jaw opening, elevated the tongue dorsum, and widened the pharynx.