1. A speech synthesis system for producing synthesized speech comprising: a large speech segment database referencing speech segments and accessed by segment designators, each segment designator being associated with a sequence of one or more speech segments; a segmental transcription database referencing segmental transcriptions associated with sequences of one or more segment designators and accessed by message designators, each message designator being associated with a fixed message; a speech segment selector for selecting a sequence of speech segments referenced by the large speech segment database and representative of a sequence of segment designators corresponding to a segmental transcription generated responsive to a message designator input; and a speech segment concatenator in communication with the large speech segment database for concatenating the sequence of speech segments selected by the speech segment selector to produce a speech signal output corresponding to the message designator input.