A challenge to be met by the present invention is to provide a voice recognition function control method and a radiocommunications system which enable use of a portable terminal even when housings of the portable terminal are closed and which enable comfortable use of the portable terminal even when the portable terminal is held in an object distant from the body as in a bag or the like. A portable cellular phone (10) establishes radio communication with a headset (20), and activates a voice recognition section (106) in response to a voice recognition start request from the headset (20). When housings are open, the function specified by the headset (20) is selected from four functions "Voice Dialing," "Voice Search," "Voice Setting," and "Camera Operation." Further, the voice recognition section (106) is controlled by use of a dictionary (108) where data used for achieving the selected function are stored. Meanwhile, when the housings are closed, the "Voice Dialing" function is selected. Further, the voice recognition section (106) is controlled by use of a dictionary (107) where data used for achieving the "Voice Dialing" function are stored.