Consonant behavior of bone conducted speech in Japanese

Bone conducted (BC) speech can be used as a tool for speech communication in highly noisy environments. This is because BC speech is insensitive to ambient noise. On the other hand, BC speech possesses a serious problem that intelligibility of BC speech is lower than that of air conducted (AC) speech. From this point of view, the mainstream of BC speech studies was to improve the intelligibility of BC speech up to now. This has resulted in the fact that inherent properties of BC speech are not clarified. There are some reports in which how BC microphone locations with intensity or intelligibility of the recorded BC speech are related has been discussed. However, only BC vowels were treated there. Consonants have never been discussed. In this paper, we investigate consonant behavior of BC speech. Through experiments, we have found two tendencies of consonants of BC speech. One is that the amplitude of voiced consonants is larger, while that of unvoiced consonants is smaller. The other is about the manner of articulation. The amplitude of nasals is the largest. Plosives have larger amplitude and fricatives have smaller amplitudes than the other consonants.