Dialectal differences in dynamic formant patterns in vowels.

This study examines basic acoustic variation in the dynamic patterns of vowel formants among three regional variants of American English spoken in southeastern Wisconsin (affected by the Northern Cities Shift), western North Carolina (Appalachian English affected by the Southern Vowel Shift), and central Ohio (not considered to be affected currently by any vowel shift). Three groups of speakers (including men and women) produced vowels in citation form (in a /hVd/ context) and in sentences. The sentence material elicited two degrees of vowel emphasis (high and low) in the /bVd/ and /bVt/ contexts. The frequencies and amplitudes of the first three formants were extracted at points corresponding to 20%-35%-50%-65%-80% of the vowel’s duration. A set of dynamic measures was then calculated using these values that included overall signed/unsigned change in formant frequencies, vector and trajectory lengths, direction/angle of vowel movement in the F1 by F2 plane, and rate of frequency change. The results show significant cross-dialectal differences in formant patterns in monophthongs, phonemic diphthongs, and nonphonemic diphthongs. The nature and extent of these formant changes varied as a function of speaker dialect in a manner apart from expected variation resulting from phonetic and prosodic context and speaking style. [Work supported by NIH.]