An artificial intelligence apparatus for recognizing speech by correcting misrecognized word includes a microphone and a processor. The processor is configured to obtain, via the microphone, speech data including speech of a user, convert the speech data into text by using an acoustic model and a language model, determine whether an uncertain recognition exists in an acoustic recognition result according to the acoustic model, determine whether the converted text is a normal sentence by using a natural language processing model if an uncertain recognition exists in the acoustic recognition result, determine a sentence most similar to the converted text among sentences pre-learned by using the language model if the converted text is not a normal sentence, replace the converted text with the determined most similar sentence, and generate a speech recognition result corresponding to the speech data by using the converted text.