A speech recognition method comprising: determining at least one activation word among a plurality of activation words based on information related to an operating environment in which a speech recognition apparatus is operating; receiving an input audio signal; performing speech recognition on the input audio signal, based on whether the input audio signal includes a speech signal of an utterance of an activation word included in the determined at least one activation word; and outputting a result of the performing of the speech recognition, wherein the performing of the speech recognition comprises: extracting text of an utterance of a user from the input audio signal, determining whether the utterance of the user includes, in the extracted text, a speech command comprising a direct command or a speech command comprising an indirect command; and wherein the direct command is determined, according to natural language understanding and sentence structure analysis of the extracted text of the speech uttered by the user, to comprise an intent for the speech recognition apparatus to output the result of the performing of the speech recognition, and wherein the indirect command is determined, according to natural language understanding and sentence structure analysis of the extracted text of the speech uttered by the user, to comprise no intent for the speech recognition apparatus to perform an operation of responding to the speech command, when it is determined that the speech command is the direct command, performing an operation of responding to the speech command,, when it is determined that the speech command is the indirect command: indicating that a response to the speech command is possible determining whether a confirmation command is detected, and in response to detecting the confirmation command from the user, performing the operation of responding to the speech command. determining at least one activation word among a plurality of activation words based on information related to an operating environment in which a speech recognition apparatus is operating; receiving an input audio signal; performing speech recognition on the input audio signal, based on whether the input audio signal includes a speech signal of an utterance of an activation word included in the determined at least one activation word; and outputting a result of the performing of the speech recognition, wherein the performing of the speech recognition comprises: extracting text of an utterance of a user from the input audio signal, determining whether the utterance of the user includes, in the extracted text, a speech command comprising a direct command or a speech command comprising an indirect command; and wherein the direct command is determined, according to natural language understanding and sentence structure analysis of the extracted text of the speech uttered by the user, to comprise an intent for the speech recognition apparatus to output the result of the performing of the speech recognition, and wherein the indirect command is determined, according to natural language understanding and sentence structure analysis of the extracted text of the speech uttered by the user, to comprise no intent for the speech recognition apparatus to perform an operation of responding to the speech command, when it is determined that the speech command is the direct command, performing an operation of responding to the speech command,, when it is determined that the speech command is the indirect command: indicating that a response to the speech command is possible determining whether a confirmation command is detected, and in response to detecting the confirmation command from the user, performing the operation of responding to the speech command. extracting text of an utterance of a user from the input audio signal, determining whether the utterance of the user includes, in the extracted text, a speech command comprising a direct command or a speech command comprising an indirect command; and wherein the direct command is determined, according to natural language understanding and sentence structure analysis of the extracted text of the speech uttered by the user, to comprise an intent for the speech recognition apparatus to output the result of the performing of the speech recognition, and wherein the indirect command is determined, according to natural language understanding and sentence structure analysis of the extracted text of the speech uttered by the user, to comprise no intent for the speech recognition apparatus to perform an operation of responding to the speech command, when it is determined that the speech command is the direct command, performing an operation of responding to the speech command,, when it is determined that the speech command is the indirect command: indicating that a response to the speech command is possible determining whether a confirmation command is detected, and in response to detecting the confirmation command from the user, performing the operation of responding to the speech command. indicating that a response to the speech command is possible determining whether a confirmation command is detected, and in response to detecting the confirmation command from the user, performing the operation of responding to the speech command.