An image display apparatus comprising: a microphone (200, 310); and a processor (210, 330) configured to: in response to obtaining a speech of a user through the microphone, obtain a first text information corresponding to the speech of the user by using text-based speech recognition, determine whether the image display apparatus is able to perform an operation based on the first text information, in response to determining that the image display apparatus is able to perform the operation based on the first text information, perform the operation based on the first text information, in response to determining that the image display apparatus is unable to perform the operation based on the first text information, provide a phonetic symbol of the first text information, obtain a second text information from a pre-stored command set of a plurality of commands, the second text information including a phonetic symbol that is same as or similar to the phonetic symbol of the first text information, and being different from the first text information and perform the operation based on the second text information. a microphone (200, 310); and a processor (210, 330) configured to: in response to obtaining a speech of a user through the microphone, obtain a first text information corresponding to the speech of the user by using text-based speech recognition, determine whether the image display apparatus is able to perform an operation based on the first text information, in response to determining that the image display apparatus is able to perform the operation based on the first text information, perform the operation based on the first text information, in response to determining that the image display apparatus is unable to perform the operation based on the first text information, provide a phonetic symbol of the first text information, obtain a second text information from a pre-stored command set of a plurality of commands, the second text information including a phonetic symbol that is same as or similar to the phonetic symbol of the first text information, and being different from the first text information and perform the operation based on the second text information. in response to obtaining a speech of a user through the microphone, obtain a first text information corresponding to the speech of the user by using text-based speech recognition, determine whether the image display apparatus is able to perform an operation based on the first text information, in response to determining that the image display apparatus is able to perform the operation based on the first text information, perform the operation based on the first text information, in response to determining that the image display apparatus is unable to perform the operation based on the first text information, provide a phonetic symbol of the first text information, obtain a second text information from a pre-stored command set of a plurality of commands, the second text information including a phonetic symbol that is same as or similar to the phonetic symbol of the first text information, and being different from the first text information and perform the operation based on the second text information.