Quantitative analysis of the effects of emphasis upon prosodic features of speech

While it is known that emphasis is represented mainly by fundamental frequency, speech rate, and source intensity, few studies have been published on the relative roles of these variables in expressing the degree of emphasis. The present paper introduces the relative speech rate and the relative source intensity of a target utterance against a reference utterance, and formulates the processes of their generation by quantitative models that are in line with the model that has been established for the fundamental frequency contour. This makes it possible to compare the effects of emphasis on the three variables in quantitative terms, as well as to compare the effects of various degrees of emphasis. Analysis of English utterances by a native speaker and a non-native speaker indicated the influence of emphasis on the three variables in quantitative terms, and also clarified the difference between native and non-native speakers.