Higher Level Organization and Discourse Prosody

This paper addresses higher level organization in discourse prosody. Fluent speech prosody of text reading illustrated higher level speech planning above phrases and prosody segments above intonation units. Adopting a top-down perspective allowed clearer reflection of scope and unit involved. We examined large amount of speech data via a corpus approach, studied read discourse through perceived boundaries, analyzed prosodic characteristics of between-boundary units, and found evidence of higher prosodic specifications above phrase intonation. Through tailored quantitative analyses corresponding to a multi-layer prosodic hierarchy, we found how different prosodic levels contribute separately to prosody output, and how cumulative contributions added up to output prosody. The prosody hierarchy specifies that speech paragraphs are immediate constituents of discourse; phrases immediate constitute of speech paragraphs. Lower level nodes are subjacent units subject to higher level constraints; sister constituents bear association to one another. Hence central to discourse prosody is higher level specification as well as cross-phrase association in addition to discrete intonation patterns. Cross-phrase cadence templates could be derived to account for the melody, rhythm, loudness and boundary breaks of fluent speech. Further, evidence of cross-paragraph discourse association is also found. We believe in addition to advance understanding of discourse prosody; the knowledge is also directly applicable to speech technology development, especially speech synthesis.