Time-varying acoustic and articulatory characteristics of American English [ɹ]: a cross-speaker study

Abstract The present study is an attempt to discover time-varying acoustic correlates of articulatory movements of American English [ɹ] using the X-ray microbeam speech production database. American English [ɹ] is known to be variable in its articulatory postures, whereas a single acoustic correlate—a low third formant—is associated with the sound. A previous study (Westbury, Hashi, & Lindstrom (1998), Speech Communication 26 , 203–226) found no relation between articulatory postures and formant frequencies at phonation onset of words beginning with the sound. The present study examined acoustic–articulatory relations in time-varying acoustic and articulatory characteristics in the transition from [ɹ] to a following low- or mid-back vowel. In intervals involving a major F3 rise, a relatively strong correlation ( r ⩾0.7) was observed between the average rate of change in F3 (F3 slope) and the speed of the tongue pellet closest to the palate at the onset of the major F3 rise. Results from the study are discussed with respect to the acoustic theory of speech production.