The present invention relates to a speech recognition system including Markov models which are adapted to be trained by an initial training label set and initial training speech using adaptation speech, and are used to recognise input speech. According to the invention, the system is characterised in that it comprises means for interpreting the adaptation speech into adaptation label strings using an adaptation label set; means for connecting each label in each of the adaptation label strings with each state or each state transition of a Markov model which corresponds to the adaptation label strings concerned; means for determining the confusion probability of each label in the initial training label set and each label in the adaptation label set being confused with each other, based on the connection between each label in the adaptation label set and each of the states or state transitions, and the parameter values of the Markov model concerned with the initial training set; and means for determining parameter values of each of the Markov models with respect to the adaptation label set, based on the confusion probabilities and the parameter values of the Markov model concerned with the initial label set.