Display apparatus, method for controlling the display apparatus, server and method for controlling the server

Disclosed is a display device. The display device comprises a voice collection unit which collects a user's voice, a first communication unit which transmits the user's voice to a first server and receives text information corresponding to the user's voice from the first server, a second communication unit which transmits the received text information to a second server and receives response information corresponding to the text information, an output unit 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 to output the response message differentiated from the response message corresponding to the previously collected user's voice if the user's voice having the same articulation intention is collected again.