Apparatus, including a sensor which is configured to be fixed to a neck of an operator of equipment in a location suitable for sensing a voiceless alaryngeal speech vibration generated by the operator during operation of the equipment, The apparatus further includes a processor which is configured to receive and process a signal output by the sensor so as to measure the voiceless alaryngeal speech vibration and so as to generate a control signal for the equipment responsively to the measured voiceless alaryngeal speech vibration.