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 inF0 contours. Three speakers read a set of 186 sentences and three paragraphs to provide data forF0 analysis. The important words in each sentence were marked intonationally with rises or sharp falls inF0, compared to gradually fallingF0 in unemphasized words. These emphasis deviations were measured in terms ofF0 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 lowerF0, and negative contractions were emphasized on their first syllables. Individual speakers differed in overallF0 levels, while using roughly similar emphasis strategies.F0 levels changed in paragraphs, with emphasis going to contextually new information.