A digital television including a display, an interface, a communication unit, a broadcast receiver, and a controller to: display broadcast content, display a screen corresponding to a voice recognition mode, receive a first voice command signal corresponding to a first voice command, which is a single voice command including a first part defining a search source of an Internet based search engine and a second part defining a first search keyword, display a web page corresponding to the search source, which includes a first search result corresponding to first information stored on a remote server, receive a second voice command signal corresponding to a second voice command, in which the second voice command is a single voice command including the first search keyword, and display a second search result corresponding to the first search keyword from the second voice command, which corresponds to second information stored in the digital television.