Comprehension of Synthetic Speech Produced by Rule: Word Monitoring and Sentence-by-Sentence Listening Times

Author: James V. Ralston, David B. Pisoni, Scott E. Lively, Beth G. Greene and John W. Mullennix

Abstract:
Previous comprehension studies using post-perceptual memory tests have often reported negligible differences in performance between natural and synthetic speech despite large differences in segmental intelligibility. The present experiments investigated the comprehension of natural and synthetic speech using two different on-line tasks: word monitoring and sentence-by-sentence listening. On-line task performance was slower and less accurate for passages of synthetic speech than natural speech. Recognition memory performance in both experiments was less accurate following passages of synthetic speech compared to natural speech. Monitoring performance, sentence listening times and recognition memory accuracy all showed moderated correlations with intelligibility scores obtained using the Modified Rhyme Test. The results suggest that the poorer comprehension of passages of synthetic speech is due, in part, to increased encoding demands relative to natural speech. Compared to earlier studies, the present results demonstrate that on-line tasks can be used to measure differences in comprehension performance between natural and synthetic speech.