9. A display device, comprising: a media data processing module configured to process media data; a media data output unit configured to output the processed media data; an audio input unit configured to receive a speech search command for additional data about the outputted media data from a user, the speech search command including at least one query word; and a processor configured to determine whether the at least one query word matches a query term that is full and searchable based on pronunciation patterns of the user, when the at least one query word matches a query term that is full and searchable and the pronunciation pattern is a first pattern, perform a search for the additional data using the query term, and when the at least one query word does not match the query term that is full and searchable and the pronunciation pattern is a second pattern, determine the query term from a predetermined amount of the audio data prior to receiving the speech search command and perform the search for the additional data using the query term, wherein the first pattern means at least one of that the user's accent is clear and that there is no mumbling in the user's pronunciation, and wherein the second pattern means at least one of that the user's accent is unclear and that there is mumbling in the user's pronunciation.
9. A display device, comprising: a media data processing module configured to process media data; a media data output unit configured to output the processed media data; an audio input unit configured to receive a speech search command for additional data about the outputted media data from a user, the speech search command including at least one query word; and a processor configured to determine whether the at least one query word matches a query term that is full and searchable based on pronunciation patterns of the user, when the at least one query word matches a query term that is full and searchable and the pronunciation pattern is a first pattern, perform a search for the additional data using the query term, and when the at least one query word does not match the query term that is full and searchable and the pronunciation pattern is a second pattern, determine the query term from a predetermined amount of the audio data prior to receiving the speech search command and perform the search for the additional data using the query term, wherein the first pattern means at least one of that the user's accent is clear and that there is no mumbling in the user's pronunciation, and wherein the second pattern means at least one of that the user's accent is unclear and that there is mumbling in the user's pronunciation. 11. The display device of claim 9 , wherein the processor is further configured to voice-recognize the predetermined amount of the audio data; extract at least one query term candidate from a corresponding voice recognition result; and determine the at least one query word that matches the query term that is full and searchable from the at least one query term candidate.