Differences among speakers in lingual articulation for American English /ɹ/

Abstract

X-ray microbeam fleshpoint measures of lingual articulation for pre-vocalic /ɹ/ were obtained for five test words spoken by 53 normal, young adult talkers of American English. The data were used to develop quantitative descriptions of cross-speaker variation in tongue shapes at acoustically-defined r-moments in the test words, and to understand whether and how /ɹ/-related tongue shapes might vary across the available sample of phonetic contexts. Key results suggest that tongue shapes for this sound vary widely across speakers within any single phonetic context, and more continuously than categorically across the representational space. Shapes also vary by context in ways that are similar across most speakers, and in some contexts, in ways that can be expected given simple assumptions about lingual movements associated with adjacent sounds. Interestingly, tongue shapes for American English /ɹ/ do not seem to be reliably linked to gender, measures of oral cavity size, or formant frequencies measured for two of the test words. Together, these results provide unique insight about the nature and bases of inter-speaker variation in lingual articulation for this infamously variable sound, and may prove useful to other investigators interested in speech motor control, speech synthesis, and automatic speech recognition.