Speaker adaptation apparatus and program thereof

A program stored in a computer readable medium, the program causing the computer to implement:

• an acquiring function to acquire an acoustic model including HMMs and decision trees for estimating what type of the phoneme or the word is included in a feature value used for speech recognition, the HMMs having a plurality of states on a phoneme-to-phoneme basis or a word-to-word basis, and the decision trees being configured to reply to questions relating to the feature value and output likelihoods in the respective states of the HMMs;
• and
• a speaker adaptation function to adapt the decision trees to a speaker, the decision trees being adapted using speaker adaptation data vocalized by the speaker of an input speech.

A speaker adaptation method comprising:

• acquiring an acoustic model including HMMs and decision trees for estimating what type of the phoneme or the word is included in a feature value used for speech recognition, the HMMs having a plurality of states on a phoneme-to-phoneme basis or a word-to-word basis, and the decision trees being configured to reply to questions relating to the feature value and output likelihoods in the respective states of the HMMs;
• and
• adapting the decision trees to a speaker, the decision trees being adapted using speaker adaptation data vocalized by the speaker of an input speech.