SUMMARYThis paper proposes a speaker adaptation method for speech recognition based on the discrete hidden Markov models (HMM), especially the fenonic Markov model, which is a framewise model. The method consists largely of two parts-the adaptation of the vector quantization codebook and the adaptation of Markov models. The former employs a method which is based on the difference between the feature parameter distributions of the training speech and the word baseform as the basis for the adaptation, where the two are divided into N segments on the time axis. The latter employs a method based on a linear mapping, which is estimated from the matching between the quantized training speech and the word baseform.In this study, a recognition experiment was executed using 150 words with high similarities. Using the speech in which all object words are uttered ten times by a male, the codebook and the Markov models are estimated as the basis for the adaptation. Then the adaptation training is executed for seven males and four females by uttering once 25 words in the object vocabulary. The average error rate, i.e., 25.0 and 45.2 percent, respectively, for the males and females. is improved to 4.1 and 7.8 percent. Thus, the usefulness of the proposed method is demonstrated.