Acoustic redundancy and the perception of time-compressed speech.

An experiment is reported in which time-compressed sentences were heard spoken either in normal intonation or in intonation patterns that conflicted with their underlying syntactic structure. Although there was an overall decrement in intelligibility with increasing compression, sentences heard in normal intonation were significantly better able to withstand the debilitating effects of compression than those with anomalous intonation. An error analysis of subject responses suggests that intonation normally operates to supply supplemental cues for determining syntactic structures as a step in the perceptual coding of heard speech.