A comparison of acoustic and articulatory methods for analyzing vowel differences across dialects : data from American and Australian English

In studies of dialect variation, the articulatory nature of vowels is sometimes inferred from formant values using the following heuristic: F1 is inversely correlated with tongue height and F2 is inversely correlated with tongue backness. This study compared vowel formants and corresponding lingual articulation in two dialects of English, standard North American English, and Australian English. Five speakers of North American English and four speakers of Australian English were recorded producing multiple repetitions of ten monophthongs embedded in the /sVd/ context. Simultaneous articulatory data were collected using electromagnetic articulography. Results show that there are significant correlations between tongue position and formants in the direction predicted by the heuristic but also that the relations implied by the heuristic break down under specific conditions. Articulatory vowel spaces, based on tongue dorsum position, and acoustic vowel spaces, based on formants, show systematic misalignment due in part to the influence of other articulatory factors, including lip rounding and tongue curvature on formant values. Incorporating these dimensions into dialect comparison yields a richer description and a more robust understanding of how vowel formant patterns are reproduced within and across dialects.