21. A speech analysis system as defined in claim 20 wherein said means for analyzing said speech signal to generate a voiced/unvoiced decision parameter further includes: means for thirdly comparing said Cepstrum peak amplitude signal with predetermined upper and lower limits and generating a voiced decision parameter if said Cepstrum peak amplitude is equal to or less than said lower limit and generating an unvoiced decision parameter if said Cepstrum peak amplitude is equal to or greater than said upper limit.
21. A speech analysis system as defined in claim 20 wherein said means for analyzing said speech signal to generate a voiced/unvoiced decision parameter further includes: means for thirdly comparing said Cepstrum peak amplitude signal with predetermined upper and lower limits and generating a voiced decision parameter if said Cepstrum peak amplitude is equal to or less than said lower limit and generating an unvoiced decision parameter if said Cepstrum peak amplitude is equal to or greater than said upper limit. 22. A speech analysis system as defined in claim 21 wherein said means for analyzing said speech signal to generate a voiced/unvoiced decision parameter further includes: means for monitoring said speech signal and counting the number of zero crossings in a predetermined time period; and means for comparing said number of zero crossings with a predetermined limit and generating an unvoiced decision parameter if said number of zero crossings is above said limit and generating a voiced decision parameter if said number of zero crossings is below said limit.