Using the method of adjustment to study vowel spaces.
Keith Johnson, RICHARD A. WRIGHT, Edward Flemming · The Journal of the Acoustical Society of America · 1992
Comparing the acoustic vowel spaces of different dialects or languages is fraught with peril because acoustic measurements confound personal and linguistic information. The study to be reported addressed this problem by using the method of adjustment. Listeners were asked to adjust the F1 and F2 of synthetic vowels to produce a perceptual match between the synthetic vowel and the vowel sound they would expect to hear in a visually presented word. The monosyllabic test words represented ten or eleven different vowel qualities (depending on dialect) for American English speakers. The listeners adjusted F1 and F2 by moving a mouse cursor, clicking the mouse button to hear the vowel sound indicated by the location of the cursor on a CRT. F3, F4, and the formant bandwidths were estimated by regression from previously reported acoustic data. Preliminary results suggested that: (1) Speakers of the same dialect were very consistent with each other; within subject variability (which was small) accounted for about 70% of all within vowel variability. (2) The method revealed perceptual vowel space differences between speakers of different dialects of American English. (3) Differences between monolingual and bilingual speakers of English from the same language community were also found. [Work supported by NIH.]