8. A non-transitory computer-readable medium storing instructions for controlling a computing device to enhance a speech database for speech synthesis, the instructions comprising: labeling audio files in a primary speech database and a secondary speech database, wherein the primary speech database and the secondary speech database are for the same language; enhancing the primary speech database by placing the labeled audio files from the secondary speech database into the primary speech database; and storing the enhanced primary speech database for use in unit selection concatenative speech synthesis.
8. A non-transitory computer-readable medium storing instructions for controlling a computing device to enhance a speech database for speech synthesis, the instructions comprising: labeling audio files in a primary speech database and a secondary speech database, wherein the primary speech database and the secondary speech database are for the same language; enhancing the primary speech database by placing the labeled audio files from the secondary speech database into the primary speech database; and storing the enhanced primary speech database for use in unit selection concatenative speech synthesis. 9. The non-transitory computer-readable medium of claim 8 , wherein the first database and the second database differ with respect to at least one of dialect, geographic language, regional language, accent, national language, idiosyncratic speech and database coverage.