1. A method for tuning grammar option weights of a phrase-based, automatic speech recognition (ASR) grammar in an unsupervised fashion comprising the steps of: recording feedback of ASR phrase processing operations during a communication session, wherein each ASR phrase processing operation matches a spoken utterance against at least one entry within a speaker dependent, phrase-based grammar, said grammar having a plurality of grammar option weights, wherein the grammar option weights affect which entries are matched to the spoken utterances; for each of the ASR phase processing operations, determining whether the phrase processing operation was successfully performed based upon the feedback; and for each of the ASR phase processing operations, automatically adjusting at least one of the grammar option weights based upon results of the determining step to improve accuracy of the grammar.