Discourse comprehension of synthetic speech by individuals with mental retardation

This study evaluated the performance of a group of individuals with mental retardation (n = 12) on a post perceptual discourse comprehension task. Additionally, data were also examine to determine the type of strategies employed by individuals with mental retardation to answer questions about discourse passages presented in synthetic speech. Three text-to-speech systems (DECTalk, MacinTalk, and Real Voice) were used to present stimulus passages. Results revealed that the DECTalk synthetic voice showed a non-significant trend towards superior accuracy scores on the comprehension task in comparison to the other two synthetic voices (i.e., MacinTalk and RealVoice). Further, plausibility strategy was used significantly (p < .01) more often to answer questions about discourse passages than direct retrieval strategy. The results of this investigation raise several issues related to the comprehension of synthetic speech by non-speaking individuals who rely on voice communication output aids for effective and efficient communication.