11. The speech recognition system of claim 6 , wherein the storage in the pronunciation variation channel unit stores a search space data therein, the search space data including a context-dependent cost function and an arc information.
6. The speech recognition system of claim 1 , wherein the pronunciation variation channel unit includes, a storage for storing the DHMM based context-dependent error model; and a Viterbi decoder for Viterbi-decoding the varied phoneme sequence to produce the word phoneme sequence by using the varied phoneme sequence Viterbi-decoded by the acoustic variation channel unit and the DHMM based context-dependent error model stored in the storage.