10. Apparatus for converting voice characteristics of synthesized speech to obtain modified synthesized speech of any one of a plurality of voice sounds simulating child-like, adult, aged and sexual characteristics from a single applied source of synthesized speech, said apparatus comprising: voice character conversion controller means for receiving digital speech data from which synthesized speech may be derived from a source thereof, said digital speech data having a predetermined pitch period, a predetermined vocal tract model and a predetermined speech rate, said voice character conversion controller means having means for selecting digital speech data representative of at least a portion of a word, and means for making a voice character selection of the synthesized speech to be derived from the digital speech data received from said source simulating a voice sound differing in character with respect to the voice sound of the synthesized speech from said source in the voice characteristics pertaining to the apparent age and/or sex of the speaker; speech parameter control means for modifying the pitch period and speech rate in response to inputs from said voice character conversion controller means as determined by said voice character selection means thereof to produce a modified pitch period and a modified speech rate; speech data reconstructing means operably associated with said speech parameter control means for combining the modified pitch period and the modified speech rate with the predetermined vocal tract model into a synthesized speech data format of speech data modified with respect to the original speech data from said source; speech synthesizer means coupled to said speech data reconstructing means for receiving the modified speech data therefrom and generating audio signals representative of human speech from the modified speech data; and audio means coupled to said speech synthesizer means for converting said audio signals into synthesized human speech having different voice characteristics from the synthesized speech which would have been obtained from the source of synthesized speech.
10. Apparatus for converting voice characteristics of synthesized speech to obtain modified synthesized speech of any one of a plurality of voice sounds simulating child-like, adult, aged and sexual characteristics from a single applied source of synthesized speech, said apparatus comprising: voice character conversion controller means for receiving digital speech data from which synthesized speech may be derived from a source thereof, said digital speech data having a predetermined pitch period, a predetermined vocal tract model and a predetermined speech rate, said voice character conversion controller means having means for selecting digital speech data representative of at least a portion of a word, and means for making a voice character selection of the synthesized speech to be derived from the digital speech data received from said source simulating a voice sound differing in character with respect to the voice sound of the synthesized speech from said source in the voice characteristics pertaining to the apparent age and/or sex of the speaker; speech parameter control means for modifying the pitch period and speech rate in response to inputs from said voice character conversion controller means as determined by said voice character selection means thereof to produce a modified pitch period and a modified speech rate; speech data reconstructing means operably associated with said speech parameter control means for combining the modified pitch period and the modified speech rate with the predetermined vocal tract model into a synthesized speech data format of speech data modified with respect to the original speech data from said source; speech synthesizer means coupled to said speech data reconstructing means for receiving the modified speech data therefrom and generating audio signals representative of human speech from the modified speech data; and audio means coupled to said speech synthesizer means for converting said audio signals into synthesized human speech having different voice characteristics from the synthesized speech which would have been obtained from the source of synthesized speech. 11. Apparatus as set forth in claim 10, wherein said digital speech data from the source is subject to speech synthesization using a predetermined sampling period comprising a known number of task-accomplishing time increments; said speech parameter control means including sample rate control circuit means responsive to inputs from said voice character conversion controller means as determined by said voice character selection means thereof for adjusting the sampling period of said digital speech data from the source in a manner altering the digital speech formants contained therein to a preselected degree and providing adjusted sampling period signals as an output; and said speech synthesizer means being coupled to the output of said sample rate control circuit means for receiving said adjusted sampling period signals therefrom as the modified speech data from said speech data reconstructing means is being input thereto.