Some articulatory and acoustic changes associated with emphasis in spoken English

In order to understand better the relationship between stress and tonal patterning of prosodic changes in spoken English, this paper examines articulatory and acoustic data of a large number of American English speakers producing prosodic minimal pairs on high and low-front vowels. Articulatory and acoustic measurements (from the x-ray microbeam database, University of Wisconsin) of 45 American English speakers’ emphasized and unemphasized vowels /i/ and /ae/ were analyzed. The results confirm previous findings that articulation and acoustics (F1,F2, and F0) change as a function of emphasis. For both emphasized /i/ and /ae/, the jaw opens more, accompanied by more extreme tongue dorsum articulation as well as more extreme formant frequencies. Results of an F0 correlation with the articulatory measures suggest there may be at least two strategies for producing emphasis: one is to rely more on F0 whereas the other is to rely more on jaw opening. These findings are relevant to developments of phonological models of articulation, and especially to the C/D Model with its view of prosody as the basis for phonetic implementation of spoken English.