Interspeaker variability in emphatic accent production in French

This research aims (1) to describe the acoustic manifestations of emphatic accent in French by examining similarities and differences between four speakers; and (2) to identify, amongst the acoustic measures, those which determine the perception of emphasis. In experiment 1, four speakers were asked to read twenty-four sentences aloud twice, first without any emphasis, and second with emphasis on a target word in the sentence. The acoustic modifications induced by emphasis production were analyzed on the target words and on their surrounding contexts, speaker by speaker. Acoustic measurements revealed that all speakers increased the contrast between the target and the contexts, by slowing down articulation on the targets and by increasing intensity and F0 on the targets relative to the adjacent syllables. F0 peak was found either on the first or last syllable of the target word, and F0 increase was shown to spread over the peak-bearing syllable to the whole word. Speakers' productions differed with respect to the production of pauses and the syllabic location of F0 peak in the target words. In Experiment 2, the four speakers' productions were presented to listeners, who had to decide whether an emphasis had been produced or not. A stepwise regression analysis was conducted, using the acoustic measurements as independent variables and the percentage of emphasis perception as the dependent variable. The results suggest a major role of F0 manifestations: Listeners were found to be sensitive to an F0 increase on the first syllable of the target, relative to its value in non-emphasis condition. Listeners would be sensitive to deviations from expected F0 patterns in French, and may interpret them as signaling emphatic accent.