Dental flaps, vowel duration and rule ordering in American English

Abstract

This paper presents the results of an experiment which investigated dental flaps and their effect upon preceding vowel duration in American English. Twenty speakers read a randomized list of 40 disyllabic words, 20 with medial /t/ and 20 with medial /d/. Most tokens of /t/ and /d/ were pronounced as flaps, as expected. The data, collected from spectrograms, included 1st and 2nd vowel duration, presence or absence of flap (as opposed to stop [t] or [d]), duration of consonant, and extent of voicing during the flap. Our results provide evidence bearing on two phonological questions: (1) Does the rule which changes /t/ and/d/ to flaps (F) precede or follow the rule which lengthens vowels before voiced consonants (VL)? If VL precedes F, the vowels preceding flaps with underlying /d/ will have greater duration than vowels preceding flaps with underlying /t/. If F precedes VL, there will be no such difference. Our results indicate a small, but significant durational difference. (2) Do underlying /t/ and /d/, in fact, give rise to the same voiced flap consonant, as is usually assumed? The data suggest that not all /t/-flaps are identical, nor are they necessarily voiced.