A display apparatus including a display unit, the display apparatus comprising: an input unit configured to receive a user's speech; a communication unit configured to perform data communication with an answer server; a processor configured to: create and display one or more question sentences using the user's speech if the user's speech is a word speech, create a question language corresponding to a question sentence selected from among the displayed one or more question sentences, transmit the question language to the answer server via the communication unit, and, if one or more answer results related to the question language are received from the answer server, display the received one or more answer results; and characterised by comprising: a storage unit configured to store a plurality of sentences, and keywords corresponding to characteristic vectors for the plurality of respective sentences, wherein the processor is arranged to measure a similarity between the stored keywords corresponding to characteristic vectors for the plurality of respective sentences previously stored in the storage unit and the word speech, to determine a sentence including a keyword measured to have a similarity equal to or greater than a predetermined threshold value with the word speech as the question sentence related to the user's speech, and to display the determined sentence. an input unit configured to receive a user's speech; a communication unit configured to perform data communication with an answer server; a processor configured to: create and display one or more question sentences using the user's speech if the user's speech is a word speech, create a question language corresponding to a question sentence selected from among the displayed one or more question sentences, transmit the question language to the answer server via the communication unit, and, if one or more answer results related to the question language are received from the answer server, display the received one or more answer results; and characterised by comprising: a storage unit configured to store a plurality of sentences, and keywords corresponding to characteristic vectors for the plurality of respective sentences, create and display one or more question sentences using the user's speech if the user's speech is a word speech, create a question language corresponding to a question sentence selected from among the displayed one or more question sentences, transmit the question language to the answer server via the communication unit, and, if one or more answer results related to the question language are received from the answer server, display the received one or more answer results; and characterised by comprising: a storage unit configured to store a plurality of sentences, and keywords corresponding to characteristic vectors for the plurality of respective sentences, wherein the processor is arranged to measure a similarity between the stored keywords corresponding to characteristic vectors for the plurality of respective sentences previously stored in the storage unit and the word speech, to determine a sentence including a keyword measured to have a similarity equal to or greater than a predetermined threshold value with the word speech as the question sentence related to the user's speech, and to display the determined sentence.