Corresponding Author:

We are grateful to Grace Yeni-Komshian, Ken Grant, Christian Lorenzi and Alain de Cheveigne ’ for insightful commentary and discussion and to Fan-Gang Zeng for comments on a previous version of this manuscript. This research is supported by NIH R01DC05660 to DP. 2 How speech signals are analyzed and represented remains a foundational challenge both for cognitive science and neuroscience. A growing body of research, employing various experimental techniques, now points to the perceptual relevance of both phoneme-sized (high modulation frequency) and syllable-sized (low modulation frequency) units in speech processing. However it is not clear how information associated with the different time scales interacts in a manner relevant for speech perception. We report behavioral experiments on speech intelligibility employing a novel stimulus that allows us to investigate how distinct temporal modulations in speech (specifically, modulation patterns associated with phonetic segments and syllables) are treated separately and how they are combined. We created sentence