The intelligiblity of nonvocoded and vocoded semantically anomalous sentences

This study consisted of an analysis of the intelligibility of semantically anomalous sentences presented to 28 subjects in four conditions (seven subjects per condition): (1) natural speech, no noise; (2) vocoded speech, no noise; (3) vocoded speech, noise added to the pitch track; (4) vocoded speech, noise added to the spectrum. Results revealed that intelligibility was quite good in conditions (1) and (2), relatively poor in (3), and quite poor in (4)—results consistent with previously obtained Diagnostic Rhyme Test (DRT) data [B. Gold and J. Tierney, Lincoln Laboratory Tech. Rep. No. 670 (1983)]. Specifically, subjects averaged 10, 25, 47, and 141 errors each in conditions (1), (2), (3), and (4), respectively. Further, about 60% of all errors were phonemic, while 40% were syntactic and semantic. We concluded that information in the spectrum is more critical than information in the pitch track, that most errors affect the phonological component when intelligibility is poor and context is uncertain, and ...