4. The speech dialogue system of claim 1, further comprising control means for controlling an updating of the filter coefficients used in the adaptive filter means according to a presence of the speech input recognized by the speech recognition means.
4. The speech dialogue system of claim 1, further comprising control means for controlling an updating of the filter coefficients used in the adaptive filter means according to a presence of the speech input recognized by the speech recognition means. 5. The speech dialogue system of claim 4, wherein the control means sets values of the filter coefficients in the adaptive filter to values before the utterance of the speech input when the presence of the speech input is recognized by the speech recognition means.