A new approach to compensate degeneration of speech intelligibility for elderly listeners-development of a portable real time speech rate conversion system

This paper presents a portable real-time speech rate conversion system which slows the input speech rate in order to compensate for the degeneration of hearing intelligibility of elderly listeners who suffers if speech is uttered rapidly. It is increasingly necessary to provide broadcasting services taking elderly listeners' hearing ability into account. It is well known that many elderly listeners have some degree of hearing impairment, including poorer absolute thresholds of audibility, lower processing speed for identification of speech and weaker effective cognitive storage capacity. The new system is designed to compensate for such deterioration by slowing the input speech rate instead of direct processing of the related auditory functions. The portable system, which can be installed in a receiver, enables the listener to convert the speech rate directly as desired in real time with invariance in pitch as well as small impairments in quality. When watching TV, the system can synchronize the converted speech with visual images at every onset of a breath group, with temporal changes in the speech rate along a monotone decreasing curve similar to temporal changes in pitch frequency.