An apparatus having both a Bluetooth-compatible transceiver and a cellular-telephony transceiver has a control circuit operably coupled to the foregoing configured to facilitate at least one on-board application using voice-based user input. The control circuit, upon determining that a call-setup message as received via the Bluetooth-compatible transceiver specifies a particular predetermined number (such as a predetermined number that comprises an invalid number to serve as a telephone number) to call, automatically uses audio content received via the Bluetooth-compatible transceiver as the aforementioned voice-based user input for that on-board application. By one approach, the apparatus can provide that predetermined number to a given secondary platform as part of a conveyed contacts list.