Patent ID: 6988069

Claim:
A method comprising: determining a desired size of a reduced unit database for text to speech operations: generating the reduced unit database of the desired size based on a full unit data base in order to minimize an overall cost in using the units in the reduced unit database to accomplish the text to speech operations; and performing the text to speech operations using the reduced unit database with respect to every sentence in a text database using units selected from the full unit database, wherein units are selected so that a cost of using the selected units to achieve text to speech is minimized; computing a unit selection cost associated with each of the sentences in the text database; and pruning the units that are selected during the text to speech operations based on the unit selection costs to produce the reduced unit database, wherein said pruning comprises: initializing the reduced unit database using the units selected during the text to speech operations performed with respect to the sentences in the text database; determining an a cost increase induced when a next unit in the reduced unit database is made unavailable for unit selection based text to speech operations; retaining the next unit in the reduced unit database if the cost increase satisfies at least one pruning criterion; and repeating said determining and said removing until at least one condition is satisfied.