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An IPA-based system has been agreed upon for labelling Swedish prosody. In the present study this system is evaluated by assessing the inter-transcriber reliability in prominence labelling of nine expert subjects. The study also explores the acoustic (F0) basis for observed variability in the assignment of focus accent, the highest prominence label.

Two experiments were designed to investigate the perceptual strength of an F0-rise relative to other possible local and global cues to focus in Swedish. The contribution of F0 relative to other possible local cues was investigated by manipulating the F0-contour in naturally produced Swedish sentences. Manipulations involved a gradual reduction of the F0-rise in focused words and a gradual addition of an F0-rise in non-focused words. The possible influence of global cues was explored by varying the amount of global information. In the first experiment, subjects were presented with complete sentences. In the second experiment, they heard sentences with the last part excluded. The results indicate that the F0-rise is neither necessary nor sufficient to perceive focus; other cues, both local and global, appear also toplay a role.

The four experiments reported concern the amount and domain of lengthening associated with focal accents in Swedish. Word, syllable and segment durations were measured in read sentences with focus in different positions. As expected, words with focal accents were longer than nonfocal words in general, but the amount of lengthening varied greatly, primarily due to speaker differences but also to position in the phrase and the word accent distinction. Most of the lengthening occurred within the stressed syllable. An analysis of the internal structure of stressed syllables showed that the phonologically long segments—whether vowels or consonants—were lengthened most, while the phonologically short vowels were hardly affected at all. Through this nonlinear lengthening, the contrast between long and short vowels in stressed syllables was sharpened in focus. Thus, the domain of focal accent lengthening includes at least the stressed syllable. Also, an unstressed syllable immediately to the right of the stressed one was lengthened in focus, while initial unstressed syllables, as well as unstressed syllables to the right of the first unstressed one, were not lengthened. Thus, we assume the domain of focal accent lengthening in Swedish to be restricted to the stressed syllable and the immediately following unstressed one.

This study deals with the perceptual relevance of a specific non-linear lengthening pattern in focally accented Swedish words, namely that found in stressed syllables where a phonologically short vowel is followed by a long consonant.

This study shows that increases in overall intensity and spectral emphasis are reliable acoustic correlates of focal accents in Swedish. They are both reliable in the sense that there are statistically significant differences between focally accented words and nonfocal ones for a variety of words, in any position of the phrase and for all speakers in the analyzed materials, and in the sense of their being useful for automatic detection of focal accents. Moreover, spectral emphasis turns out to be the more reliable correlate, as the influence on it of position in the phrase, word accent and vowel height was less pronounced and as it proved a better predictor of focal accents in general and for a majority of the speakers. Finally, the study has resulted in data for overall intensity and spectral emphasis that might prove important in modeling for speech synthesis.