11. The speech processor in claim 7, wherein said pitch detector comprises a vowel pitch detector and a consonant pitch detector; said vowel pitch detector comprising means to receive said comparator output signal and calculating a vowel pitch length for high amplitude signals and large values of said autocorrelation function that are typical for vowel sounds; said consonant pitch detector comprising means to receive said comparator output signal and calculating a consonant pitch length for low amplitude signals and small values of the autocorrelation function that are typical for consonant sounds.
11. The speech processor in claim 7, wherein said pitch detector comprises a vowel pitch detector and a consonant pitch detector; said vowel pitch detector comprising means to receive said comparator output signal and calculating a vowel pitch length for high amplitude signals and large values of said autocorrelation function that are typical for vowel sounds; said consonant pitch detector comprising means to receive said comparator output signal and calculating a consonant pitch length for low amplitude signals and small values of the autocorrelation function that are typical for consonant sounds. 12. The speech processor in claim 11, wherein said vowel pitch length is determined as the distance between two local maximums of the autocorrelation function which satisfy three conditions: (i) the vowel pitch length L.sub.v is between 50 and 200 msec, (ii) the adjusted pitches differ not more than about five percent (5%), and (iii) the local maximums of the autocorrelation function that marks the beginning and the end of each pitch are larger than any local maximums between them.