Coarticulatory stability in American English /r/

A number of different researchers have reported a substantial degree of variability in how American English /r/ coarticulates with neighboring segments. Acoustic and articulatory data were used to investigate this variability for speakers of “rhotic” American English dialects. The major issue addressed is the degree to which segmental context affects articulatory movement as reflected in the F3 trajectory. In particular, we ask whether the duration of the F3 trajectory is affected by conflicting vs. nonconflicting articulatory specifications. The F3 formant trajectory durations were measured by an automatic procedure and compared for nonsense words of the form /´waCrav/ and /waC´rav/, where C indicates a labial, alveolar or velar consonant and ´ marks the syllabic stress. These durations were compared to F3 trajectory durations in /´warav/ and /wa´rav/. Results indicated F3 trajectory durations were similar across consonant contexts, suggesting that coarticulation of /r/ is achieved by overlap of a stable /r/-related articulatory gesture with gestures for neighboring sounds. This interpretation, and the concordance of F3 time course with tongue movement for /r/, was supported by direct measures of tongue movement for one subject