15. A computer-readable storage medium according to claim 13 , further including instructions for causing the one or more processors to perform the step of: generating a text file containing the text string, wherein the text file has a file name as the unique identifier.
13. A computer-readable storage medium carrying one or more sequences of one or more instructions for providing speech synthesis, the one or more sequences of one or more instructions including instructions which, when executed by one or more processors, cause the one or more processors to perform the steps of: receiving a text string; determining whether a rendered audio file of the text string exists; if the rendered audio file does not exist, creating an audio file rendering of the text string, wherein the audio file is stored for retrieval upon subsequent receipt of the text string; and generating a unique identifier derived from the received text string according to a hash function, wherein the stored rendered audio file is identified based on the unique identifier that includes a hash index.