Stress-induced variation in F2 trajectories as evidence for coproduction in CV syllables

This study explored the extent to which a model of the acoustic consequences of overlapping, sliding consonantal and vocalic gestures was used to account for stress-induced changes in F2 trajectories occurring in test words embedded in a carrier phrase. Three stress conditions were studied including contrastive stress on test words (CS), contrastive stress on the content word preceding test words (U-CS), and non contrastive stress on test words (NS). F2 onset frequency was used to quantify the extent to which adjacent consonantal and vocalic gestures in stop consonant + vowel syllables were coproduced (i.e., overlapped) in the different stress conditions. The predicted relationship between F2 onset frequency and temporal variation in trajectories was also examined within and across stress conditions. In addition, the effects of stress-induced variation in articulatory scaling on F2 onset frequency were studied and factored into the interpretation of the results. The results indicated that F2 onset frequencies tended to differ for stress conditions characterized by large differences in prominence. Regression analyses predicting temporal variation in trajectories from F2 onset frequency accounted for part of the variance within and across stress conditions. Taken together, the results suggested that a model of overlapping, sliding gestures accounts for only some of the stress-induced variability in F2 trajectories in the current study.