6. The construction method according to claim 1 , wherein the step of constructing at least one of an acoustic model and a language model comprises: a step, executed by the computer system, of training a language model which contains, as a language unit, the unit which represents the simultaneous speech segment, based on the transcript of the speech of the mixed speakers.
6. The construction method according to claim 1 , wherein the step of constructing at least one of an acoustic model and a language model comprises: a step, executed by the computer system, of training a language model which contains, as a language unit, the unit which represents the simultaneous speech segment, based on the transcript of the speech of the mixed speakers. 7. The construction method according to claim 6 , wherein the step of constructing at least one of an acoustic model and a language model further comprises the steps, executed by the computer system, of: determining weighting for use in uniting a language model containing the language unit which represents the simultaneous speech segment with another language model; and forming a language model which makes up the speech recognition model by uniting the language model containing the language unit which represents the simultaneous speech segment with the other language model based on the weighting.