A SIMPLIFIED MODEL FOR THE SIMULATION AND TRANSFORMATION OF SPEECH

This paper explores a model that reduces speech production to the spec ification of four time-varying parameters; F1 and F2, voice fundamenta l frequency (F-0), and a relative amplitude of the voice. The trajecto ry of the first two formants, F1 and F2, is treated as a series of coo rdinate pairs that are mapped from the F1F2 plane into a two-dimension al plane of coefficients. These coefficients are multipliers of two em pirically-based orthogonal basis vectors which, when added to a neutra l vowel area function, will produce a new area function with the desir ed locations of F1 and F2. Thus, area functions and voice parameters e xtracted at appropriate time intervals can be fed into a speech simula tion model to recreate the original speech. A transformation of the sp eech can also be imposed by manipulating the area function and voice c haracteristics prior to the recreation of speech by simulation. The mo del has initially been developed for vowel-like speech utterances, but the effect of consonants on the F1F2 trajectory is also briefly addre ssed (C) 1998 Published by Elsevier Science Ltd. All rights reserved.