Stop-like modification of the dental fricative /ð/: an acoustic analysis.

This study concentrates on one of the commonly occurring phonetic variations in English: the stop-like modification of the dental fricative /ð/. The variant exhibits a drastic change from the canonical /ð/; the manner of articulation is changed from one that is fricative to one that is stop-like. Furthermore, the place of articulation of stop-like /ð/ has been a point of uncertainty, leading to confusion between stop-like /ð/ and /d/. In this study, acoustic and spectral moment measures were taken from 100 stop-like /ð/ and 102 /d/ tokens produced by 59 male and 23 female speakers in the TIMIT corpus. Data analysis indicated that stop-like /ð/ is significantly different from /d/ in burst amplitude, burst spectrum shape, burst peak frequency, second formant at following-vowel onset, and spectral moments. Moreover, the acoustic differences from /d/ are consistent with those expected for a dental stop-like /ð/. Automatic classification experiments involving these acoustic measures suggested that they are salient in distinguishing stop-like /ð/ from /d/.