An embodiment of the present disclosure provides a display device for adjusting recognition sensitivity of a speech recognition starting word, the display device including a display, a microphone, a memory configured to store a default starting word recognition engine that recognizes a speech recognition starting word, and a processor configured to determine a valid recognition threshold range of the default starting word recognition engine, assign recognition thresholds within the valid recognition threshold range to a predetermined number of sensitivity levels, display a sensitivity setting interface including the sensitivity levels through the display, and set a default recognition threshold of the default starting word recognition engine to a recognition threshold selected through the sensitivity setting interface.