Provided are a terminal and server of a speaker-adaptation speech-recognition system and a method for operating the system. The terminal in the speaker-adaptation speech-recognition system includes a speech recorder which transmits speech data of a speaker to a speech-recognition server, a statistical variable accumulator which receives a statistical variable including acoustic statistical information about speech of the speaker from the speech-recognition server which recognizes the transmitted speech data, and accumulates the received statistical variable, a conversion parameter generator which generates a conversion parameter about the speech of the speaker using the accumulated statistical variable and transmits the generated conversion parameter to the speech-recognition server, and a result displaying user interface which receives and displays result data when the speech-recognition server recognizes the speech data of the speaker using the transmitted conversion parameter and transmits the recognized result data.