A display apparatus (100) is disclosed. The display apparatus (100) includes a voice collecting unit which collects a user's voice; a first communication unit which transmits the user's voice to a first server (200), and receives text information corresponding to the user's voice from the first server (200); a second communication unit which transmits the received text information to a second server (300), and receives response information corresponding to the text information; an output unit (140) which outputs a response message corresponding to the user's voice based on the response information; and a control unit which controls the output unit (140) to output a response message differentiated from a response message corresponding to a previously collected user's voice, when a user's voice having a same utterance intention is re-collected.