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A series of experiments was conducted to examine the influence of contrastive stress on intonational patterns of duration and fundamental voice frequency (F0). In a preliminary study, intonational patterns in spontaneous speech were compared with the patterns in oral reading of the transcribed spontaneous material. In both circumstances, a general declination of F0 peaks throughout the course of a sentence was not regularly observed, contrary to earlier findings with oral reading of isolated sentences. Two experiments were then conducted to examine the possibility that the general absence of declination observed here might be due to the influence of sentence focus, following previous results from Swedish showing that declination was not observed consistently in isolated sentences until after the site of focus. In experiment 1, we found no evidence of this restriction on declination in the oral reading of English declaratives. Declination was observed both before and after the focused item in a sentence. Furthermore, our analyses revealed that focus (as manifested by contrastive stress) is generally accompanied by an increase in duration on the focused word and by a sharp drop in F0 following the focused item. In experiment 2, these effects were replicated and extended using longer sentences. In both experiments, the influence of focus was strictly localized to the site of focus in the case of duration, but not F0. The results for both duration and F0 indicate that the influence of focus assignment on these attributes varies systematically as a function of the focus location in the sentence. Finally, the combined elongation effects for focus and utterance-final lengthening were less than would be predicted by an additive model, suggesting the operation of an expandability constraint on segmental lengthening in speech production.

An acoustical study of speech production was conducted to determine the manner in which the location of linguistic focus influences intonational attributes of duration and fundamental voice frequency (F0) in matched statements and questions. Speakers orally read sentences that were preceded by aurally presented stimuli designed to elicit either no focus or focus on the first or last noun phrase of the target sentences. Computer-aided acoustical analysis of word durations showed a localized, large magnitude increase in the duration of the focused word for both statements and questions. Analysis of F0 revealed a more complex pattern of results, with the shape of the F0 topline dependent on sentence type and focus location. For sentences with neutral or sentence-final focus, the difference in the F0 topline between questions and statements was evident only on the last key word, where the F0 peak of questions was considerably higher than that of statements. For sentences with focus on the first key word, there was no difference in peak F0 on the focused item itself, but the F0 toplines of questions and statements diverged quite dramatically following the initial word. The statement contour dropped to a low F0 value for the remainder of the sentence, whereas the question remained quite high in F0 for all subsequent words. In addition, the F0 contour on the focused word was rising in questions and falling in statements, regardless of focus location. The results provide a basis for work on the perception of linguistic focus.