49. A system for speech synthesis comprising: a processor; and a storage medium having program instructions written thereon for execution on the processor, the program instructions including program instructions for: a front end module configured to receive symbolic input descriptive of an utterance to be synthesized, a back end module configured to select a portion of the utterance to be constructed from a speech unit of a speech corpus, the speech unit recorded from a human speaker, the speech unit lacking transitions at one or both of the speech unit's edges, a synthesis module configured to synthesize a transition for use at an edge of the speech unit by use of Rule-Based Speech Synthesis (RBSS) rules, and a concatenation engine of the back end module configured to concatenate the speech unit with the synthesized transition in production of a speech waveform for the utterance.
49. A system for speech synthesis comprising: a processor; and a storage medium having program instructions written thereon for execution on the processor, the program instructions including program instructions for: a front end module configured to receive symbolic input descriptive of an utterance to be synthesized, a back end module configured to select a portion of the utterance to be constructed from a speech unit of a speech corpus, the speech unit recorded from a human speaker, the speech unit lacking transitions at one or both of the speech unit's edges, a synthesis module configured to synthesize a transition for use at an edge of the speech unit by use of Rule-Based Speech Synthesis (RBSS) rules, and a concatenation engine of the back end module configured to concatenate the speech unit with the synthesized transition in production of a speech waveform for the utterance. 55. The system of claim 49 wherein the speech corpus is a target voice corpus recorded from a target speaker and configured to provide characteristics of a target voice.