A display apparatus is provided. The display apparatus includes: an output unit; a voice collector which collects a user's voice; a first communication unit which transmits the user's voice to a first server and receives text information which corresponds to the user's voice; a second communication unit which transmits the received text information to a second server; and a controller which, when response information which corresponds to the text information is received, controls the output unit to output a system response which corresponds to an utterance intention of the user based on the response information, and when the user's utterance intention is related to at least one of performance of a function of the display apparatus and a search for a content, the system response includes an additional question which relates to the at least one of the performance of the function and the search for the content.