19. An apparatus for adapting a model for a speech recognition system using an adaptation process, the apparatus comprising: a processor that is operable to determine an error rate, corresponding to either recognition of instances of a word or recognition of instances of various words among a set of words; and a controller that is operable to adjust an adaptation process for the model for the word or various models for the various words, based on the error rate.
19. An apparatus for adapting a model for a speech recognition system using an adaptation process, the apparatus comprising: a processor that is operable to determine an error rate, corresponding to either recognition of instances of a word or recognition of instances of various words among a set of words; and a controller that is operable to adjust an adaptation process for the model for the word or various models for the various words, based on the error rate. 30. The apparatus of claim 19 , wherein the error rate threshold is based a measure of difficulty of the recognition of the word.