55. The speech synthesizer of claim 54 further including first modulating means for modulating the amplitude of said voiced excitation signal in accordance with a first of said control signals produced by said input means whenever a phoneme requiring vocal energy is to be generated, and second modulating means for modulating the amplitude of said unvoiced excitation signal in accordance with a second of said control signals produced by said input means whenever a phoneme requiring fricative energy is to be produced.
55. The speech synthesizer of claim 54 further including first modulating means for modulating the amplitude of said voiced excitation signal in accordance with a first of said control signals produced by said input means whenever a phoneme requiring vocal energy is to be generated, and second modulating means for modulating the amplitude of said unvoiced excitation signal in accordance with a second of said control signals produced by said input means whenever a phoneme requiring fricative energy is to be produced. 59. The speech synthesizer of claim 55 further including amplitude control means responsive to said input data to vary the relative overall amplitude of said audio output by continuously modulating a preselected signal characteristic of said first and second control signals by a certain percentage determined by said input data.