15. The method as claimed in claim 14 , further comprising registering the user command according to a similarity between a text for the user command and a text for a spoken voice in response to the spoken voice for the user command being input in a state in which the audio for the user command is output.
15. The method as claimed in claim 14 , further comprising registering the user command according to a similarity between a text for the user command and a text for a spoken voice in response to the spoken voice for the user command being input in a state in which the audio for the user command is output. 16. The method as claimed in claim 15 , wherein in the registering of the user command, the registration suitability for the user command is determined, and the user command is registered according to a selection command of the user in a case in which the registration for the user command does not belong to both of a suitable case and an unsuitable case.