Abstract:
The average life span of the Japanese has been drastically extended in recent decades thanks to developments in medical science and treatments. Considerations for the aged are demanded in every aspect of social life including voice announcements by synthetic speech. The real situation of hearing synthetic speech by aged persons is clarified through dictation tests on synthetic speech generated by a commercial synthesizer system using texts from Murphy's law for 58 subjects aged 10 to 80 years old. In order to investigate the effects of hearing loss and language ability, dictation results were compared with results of hearing tests for sinusoidal waves and language ability tests by various types of written and oral tests. Dictation scores of primary school children and aged persons show larger variances compared with those for subjects 20--59 years old. Rates of mishearing by aged persons having hearing difficulty sometimes exceed 50% in mora units, although those of primary school children remain within 18% at the most. The correlation coefficient between dictation score and comprehension score was 0.76. Occurrence rates of phonemic confusion on plosive sounds by subjects with hearing difficulty show clear differences between voiced plosives and unvoiced plosives. [Work supported by STA, Japan.]