Dynamic speaker adaptation in the Harpy speech recognition system

The Harpy speech recognition system works optimally when it "knows" the speaker, i,e. when it has learned the speaker dependent characteristics (speaker dependent parameters) of the speaker. There are three methods of learning these parameters. One way is to generate them from a set of training data which covers all the allophones that occur in the task language. A second method is to use "speaker independent" parameters with a resulting reduction in accuracy performance. Since it is inconvenient for a "new" speaker to say a set of training data before using the system and the low accuracy with speaker independent parameters is unacceptable, a third method has been devised to allow the system to dynamically learn the speaker dependent parameters while using the system. The new speaker starts with a set of speaker independent parameters. These parameters are then altered after correct recognition (which can be forced if necessary) to match the spoken utterance.