1. A method of recognizing voice input commands by a display device, the method comprising: displaying a list of preset words that are available for receiving as input, wherein at least one of the preset words comprises a description for a natural language word that is available for input with the at least one of the preset words; receiving a first voice input comprising (i) a preset word that is a first portion of the first voice input and (ii) a natural language word that is a second portion of the first voice input; recognizing, by a first voice recognizing unit, the preset word that is the first portion of the first voice input as a preset voice command to be processed by the first voice recognizing unit; recognizing, by the first voice recognizing unit, the natural language word that is the second portion of the first voice input as a natural language voice command to be processed by a second voice recognizing unit; processing the preset voice command, by the first voice recognizing unit; processing the natural language voice command, by the second voice recognizing unit; and controlling a feature of the display device according to the processed preset voice command and the processed natural language voice command.