Abstract: A command for application program is generated based on both a movement of a cursor on a display unit depending upon operation of a pointing device and a voice produced in parallel to the operation when the pointing device is operated to select an object being displayed on the display unit connected to a computer. Particularly, if a moving speed of the cursor in a region of the object has a local minimum value which is less than a predetermined speed, the object is selected as a referent candidate for the voice containing a demonstrative word. If a plurality of referent candidates each having the local minimum value less than the predetermined speed are present for the voice containing the demonstrative word, such object is recognized as a referent for the voice that a time period during when the cursor moves in a region overlaps at maximum with a time period during when the voice is produced.