A voice-generation system using an intramouth vibrator

This paper proposes and evaluates an intramouth vibrating voice-generation system we have developed to aid alaryngeal speech. The system fixes a vibrator in artificial teeth as a substitute for a glottal sound source, and proper sound control improves the speech. With this system, we controlled the substitute glottal sound with intraoral pressure, which increases for voiceless consonants, for clearer speech. In addition, the system controls the pitch of speech using pressure from a finger. This concise pitch control is available to all patients for more natural speech. We tested two methods of pitch control by finger pressure: one in which finger pressure directly determines the pitch, and the other in which finger pressure is converted into binary commands of voice and accent that execute pitch pattern generation. Conventional pitch control with expiration pressure served as a reference. Without voicing control, less than 50% of syllables were identified correctly. Voicing control improved this rate to 60%. Similarly, voicing control improved misidentification of voiceless consonants to corre-sponding voiced ones from 30% to 10%. Binary pitch control with finger pressure performed better than direct pitch control and was perceived as natural as direct pitch control with expiration pressure.