INTELLIGIBILITY OF NORMAL SPEECH .1. GLOBAL AND FINE-GRAINED ACOUSTIC-PHONETIC TALKER CHARACTERISTICS

This study used a multi-talker database containing intelligibility sco res for 2000 sentences (20 talkers, 100 sentences), to identify talker -related correlates of speech intelligibility. We first investigated ' 'global'' talker characteristics (e.g., gender, F0 and speaking rate). Findings showed female talkers to be more intelligible as a group tha n male talkers. Additionally, we found a tendency for F0 range to corr elate positively with higher speech intelligibility scores. However, F 0 mean and speaking rate did not correlate with intelligibility. We th en examined several fine-grained acoustic-phonetic talker-characterist ics as correlates of overall intelligibility. We found that talkers wi th larger vowel spaces were generally more intelligible than talkers w ith reduced spaces. In investigating two cases of consistent listener errors (segment deletion and syllable affiliation), we found that thes e perceptual errors could be traced directly to detailed timing charac teristics in the speech signal. Results suggest that a substantial por tion of variability in normal speech intelligibility is traceable to s pecific acoustic-phonetic characteristics of the talker. Knowledge abo ut these factors may be valuable for improving speech synthesis and re cognition strategies, and for special populations (e.g., the hearing-i mpaired and second-language learners) who are particularly sensitive t o intelligibility differences among talkers.