Linguistic modality effects on fundamental frequency in speech.

This paper examines the effects on fundamental frequency (F0) patterns of modality operators, such as sentential adverbs, modals, negatives, and quantifiers. These words form inherently contrastive classes which have varying tendencies to produce emphasis deviations in F0 contours. Three speakers read a set of 186 sentences and three paragraphs to provide data for F0 analysis. The important words in each sentence were marked intonationally with rises or sharp falls in F0, compared to gradually falling F0 in unemphasized words. These emphasis deviations were measured in terms of F0 variations from the norm; they were larger toward the beginning of sentences, in longer sentences, on syllables surrounded by unemphasized syllables, and in contrastive contexts. Other results showed that embedded clauses tended to have lower F0, and negative contractions were emphasized on their first syllables. Individual speakers differed in overall F0 levels, while using roughly similar emphasis strategies. F0 levels changed in paragraphs, with emphasis going to contextually new information.