1. An electronic apparatus comprising: a voice recognizer configured to recognize a user's voice; a storage configured to have previously stored instructions; a function executor configured to perform a predetermined function; and a controller configured to: make a first determination whether or not the user's voice comprises a voice selection command for using a dialogue mode; in response to the first determination that the user's voice comprises the voice selection command, skip an instruction mode and provide voice following the voice selection command to an external server for external analyzing and based on results of the external server analyzing of the voice, control the function executor to execute the predetermined function, and in response to the first determination that the user's voice does not comprise the voice selection command, make a second determination whether the user's voice matches an instruction of the previously stored instructions, in response to the second determination indicating that the user's voice matches the instruction of the previously stored instructions, execute the instruction mode in which the user's voice is processed internally within the electronic apparatus and control the function executor to execute the predetermined function corresponding to the instruction, and in response to the second determination indicating that the user's voice does not match any of the previously stored instructions, provide the user's voice to the external server for external analyzing.