SPEECH RECOGNITION APPARATUS AND METHOD UTILIZING A LANGUAGE MODEL PREPARED FOR EXPRESSIONS UNIQUE TO SPONTANEOUS SPPECH

A speech recognition apparatus can include a transformation processor configured to transform at least one phoneme sequence included in speech into at least one word sequence, and to provide the word sequence with an appearance probability indicating that the phoneme sequence originally represented the word sequence. A renewal processor can renew the appearance probability based on a renewed numerical value indicated by language models corresponding to the word sequence provided by the transformation processor. A recognition processor can select one of the word sequences for which the renewed appearance probability is the highest to indicate that the phoneme sequence originally represented the selected word sequence. The renewal processor can calculate the renewed numerical value using a first language model prepared for expressions unique to spontaneous speech, and a second language model different from the first which employs the renewed numerical value to renew the appearance probability.