Coarticulatory stability in American English /./

A number of different researchers have reported a substantial degree of variability in how American English /./ coarticulates with neighboring segments. Acoustic and articulatory data were used to investigate this variability for speakers of ‘‘rhotic’’ American English dialects. Three issues were addressed: ~1! the degree to which the F3 trajectory is affected by segmental context and stress, ~2! to what extent the data support a ‘‘coproduction’’ versus a ‘‘spreading’’ model of coarticulation, and ~3! the degree to which the major acoustic manifestation of American English /./—the time course of F3—reflects tongue movement for /./. The F3 formant trajectory durations were measured by automatic procedure and compared for nonsense words of the form /’waCrav/ and /wa’Crav/, where C indicates a labial, alveolar, or velar consonant. These durations were compared to F3 trajectory durations in /’warav/ and /wa’rav/. In addition, formant values in initial syllables of words with and without /./ were examined for effects of intervening consonant contexts. Results indicated similar F3 trajectory durations across the different consonant contexts, and to a lesser degree across stress, suggesting that coarticulation of /./ can be achieved by overlap of a stable /./-related articulatory trajectory with movements for neighboring sounds. This interpretation, and the concordance of F3 time course with tongue movement for /./, was supported by direct measures of tongue movement for one subject. © 1997 Acoustical Society of America. @S0001-4966~97!02106-1#