A method for controlling operation of an agricultural machine and system thereof are disclosed. The method may comprise providing a portable device that has an input device, a processing unit, a storage unit, an output device, and a transceiver device configured for wireless data transmission； receiving a voice control command over a microphone device of the input device of the portable device； determining command text data from the voice control command by processing the voice control command by a speech recognition application running on the processing unit of the portable device； providing machine control signals assigned to a machine control function in a control device of an agricultural machine located remotely from the portable device； and controlling the operation of the agricultural machine according to the machine control signals.
