5th International Conference on Spoken Language Processing
Resolution of the fundamental frequency of speech sound required for the design of a speech processor of a cochlear implant device is investigated, with special regard to transmitting voice pitch information in Asian languages. Clinical application of the cochlear implant has spread rapidly in recent years to Asian countries where a variety of languages having different voice pitch information from English and other European languages are spoken. The perceptually acceptable area and required resolution of duration and fundamental frequency is estimated on a two-dimensional chart consisting of logarithmic time and frequency scales, based on the typical voice pitch contours of Japanese word accent and Chinese syllabic tone. As a result, it is shown that much finer quantizing and time sampling for the change in fundamental frequency is required compared with sentence intonation and emphasis common to other languages. It is also shown that the amount of information conveyed by combined use of lipreading with a cochlear implant is not sufficient for supplementing the voice pitch information. A possible way of transmitting such voice pitch information by transmission of the waveform of speech sound directly to the auditory area of cortex, where the waveform is reconstructed and voice pitch is extracted, is discussed.
Bibliographic reference. Hiki, Shizuo / Imaizumi, Kazuya / Fukuda, Yumiko (1998): "Design of cochlear implant device for transmitting voice pitch information in speech sound of asian languages", In ICSLP-1998, paper 1091.