A cineradiograhic study of static and dynamic aspects of American English /r/.

High speed cineradiograms were used to examine the articulatory characteristics associated with selected allophones of American English /r/. Only one of the three speakers produced a 'retroflexed' /r/ with a raised tongue apex. The other speakers produced a 'bunched' /r/ characterized by a raising of the tongue dorsum. Two basic types of /r/ were observed for all three speakers: (1) prevocalic /r/, which initiated a syllable, and (2) post-vocalic /r/, which terminated a syllable or formed a syllabic nucleus. The prevocalic allophone was characterized by greater lip rounding, a more advanced tongue position, and less tongue dorsum grooving. The two allophones also were associated with different variability and movement attributes. The differences in /r/ allophones were found to be similar to previously reported differences in American English /l/ allophones.