The effect of stress on consonant vowel (CV) coarticulation: Decoupling of the CV bond

Two common sources of variation in the speech signal arise from (1) naturally imposed speaking conditions (e.g., stress, tempo), overlaid onto (2) inherent contextual influences. Coarticulatory analyses are affected by both sources of variation, but rarely are they dissociated. The focus of this study was to derive quantitative methods to assess the effect of emphatic vowel stress on preceding stop consonant onsets, apart from, and independent of, anticipatory effects of changing vowel contexts. Three speakers produced V1CV2 tokens, with emphatic stress either on V1 or V2; C=/bdg/. There were six V1 and 10 V2 vowel contexts. Novel methods were applied to both standard locus equation scatterplots and multiple regression analyses to isolate F2 midvowel (Hz) and F2 onset (Hz) adjustments as a function of emphatic stress. The analyses show how stress differentially affects the V-midpoints and C-onsets for labial /b/ relative to lingual stops /dg/.