A method and apparatus for analyzing and synthesizing speech information in which a predetermined vocabulary is spoken into a microphone, the resulting electrical signals are differentiated with respect to time, digitized, and the digitized waveform is appropriately expanded or contracted by linear interpolation so that the pitch periods of all such waveforms have a uniform number of digitizations and the amplitudes are normalized with respect to a reference signal. These 'standardized' speech information digital signals are then compressed in the computer by subjectively removing preselected relatively low power portions of the signals by a process termed 'X period zeroing' and by discarding redundant speech information such as redundant pitch periods, portions of pitch periods, redundant phonemes and portions of phonemes, redundant amplitude information (delta modulation) and phase information (Fourier transformation). The compression techniques are selectively applied to certain of the speech information signals by listening to the reproduced, compressed information. The resulting compressed digital information and associated compression instruction signals produced in the computer are thereafter injected into the digital memories of a digital speech synthesizer where they can be selectively retrieved and audibly reproduced to recreate the original vocabulary words and sentences from them.
Method and apparatus for speech synthesizing