Articulation of extreme formant patterns for emphasized vowels

This study examined formant, jaw and tongue dorsum measurements from X-ray microbeam recordings of American English speakers producing emphasized vs. unemphasized words containing high-front, mid-front and low vowels. For emphasized vowels, the jaw position, regardless of vowel height, was lower, while the tongue dorsum had a more extreme articulation in the direction of the phonological specification of the vowel. For emphasized low vowels, the tongue dorsum position was lower with the acoustic consequence of F1 and F2 bunched closer together. For emphasized high and mid-front vowels, the tongue was more forward with the acoustic consequence of F1 and F2 spread more apart. These findings are interpreted within acoustic models of speech production. They also provide empirical data which have application to the C/D model hypothesis that both increased lowering of jaw and enhanced tongue gesture are consequences of a magnitude increase in the syllable pulse due to emphasis.