A hypothesis about the relationship between prosodic structure and discourse structure in English was tested by taking into consideration explicit models of both intonational structure and discourse structure in constructing the experimental corpus. In the experiment, a corpus of discourses with controlled structure was read by speakers. Matched pairs of utterances were extracted from different positions in the discourses. These pairs were played to listeners to test whether the discourse position was distinguishable. The utterances were then ToBI transcribed in order to test whether the same dominance relationships in the discourses are reflected by the same edge tones. Then, pairs which were perceptually distinct were examined for tonal similarity. Finally, pairs of utterances which were perceptually distinct and which had similar tones were analyzed acoustically for phonetic differences. Several trends emerged in the acoustic analysis, including differences in fundamental frequency, root mean square amplitude, and duration. These phonetic factors were thus bearing the functional load of indicating more global aspects of discourse structure.