Perception Studies on the Attributes of Synthetic Clear Speech for the Hard of Hearing

We make a case for ‘synthetic clear speech’ in the context of the persons with hearing impairment. We study the acoustic attributes of ‘clear speech’ that enable us to understand their importance in speech perception. Our perception experiments are motivated by the growing body of research emphasizing the significance of clear speech, as opposed to conversation or conventional speech, in the context of the hearing-impaired. Specifically, we study the role of the two important attributes of clear speech namely, the consonant-to-vowel intensity ratio (CVR) and the consonant duration (CD). We have developed a computerized test administration system to study the response of the ‘simulated’ impaired hearing listeners to modifications in the CVR and CD. Our perception studies using the stop consonants of the English language show that the CVR and the formant transition duration play an important role in speech perception. We believe that our findings will be useful in developing appropriate speech signal processing mechanisms to improve speech perception in the hard of hearing.