Abstract: An improved text-to-speech synthesizer that employs a text to speech converter, a text reader control procedure, a classifier procedure, an abbreviation expansion procedure, and an acronym/initialism expanding procedure is herein described. A classifier procedure is used to classify generate classification values for each word in the text message with regard to syntax, punctuation and membership in predefined classes of words, the predefined classes of words including number, measurement units, geographic designations, and date/time values. An abbreviation expansion procedure evaluates, based on the classification values for words neighboring the identified words, which, if any, of the potential expansion values is applicable, and substitutes the potential expansion for the identified abbreviation word when evaluation yields a success value.

Abstract: A text-to-speech conversion system converts specified text strings into corresponding strings of consonant and vowel phonemes. A parameter generator converts the phonemes into formant parameters, and a formant synthesizer uses the formant parameters to generate a synthetic speech waveform. A library of vowel allophones are stored, each stored vowel allophone being represented by formant parameters for four formants. The vowel allophone library includes a context index for associating each said vowel allophone with one or more pairs of phonemes preceding and following the corresponding vowel phoneme in a phoneme string. When synthesizing speech, a vowel allophone generator uses the vowel allophone library to provide formant parameters representative of a specified vowel phoneme. The vowel allophone generator coacts with the context index to select the proper vowel allophone, as determined by the phonemes preceding and following the specified vowel phoneme.