A speech recognition apparatus and an operating method thereof which execute a mounted artificial intelligence (AI) algorithm and/or machine learning algorithm to perform speech recognition and communicate with different electronic apparatuses and external servers in a 5G communication environment are disclosed. A speech recognition method according to an exemplary embodiment of the present disclosure includes determining a temporary pause for reception of a first utterance sentence in the middle of the reception of the first utterance sentence, outputting a speech recognition processing result of a second utterance sentence which is received after the temporary pause, separately from the first utterance sentence, determining a third utterance sentence which is received after outputting the speech recognition processing result of the second utterance sentence as an extension of the first utterance sentence, and outputting a speech recognition processing result of a fourth utterance sentence obtained by combining the first utterance sentence and the third utterance sentence. According to the present disclosure, a delay occurring in the middle of reception of uttering speech is recognized as an uncompleted utterance to be temporarily stored and a speech recognition processing result for an additional uttering speech received after the delay is provided and then uttering speech which is input again and the uttering speech before the delay are recognized as completed utterance and a speech recognition processing result is provided to improve the speech recognition processing performance.