An electronic device, comprising: a microphone; at least one processor; and a memory storing programming instructions executable by the at least one processor to cause the electronic device to: receive, using the microphone, a first speech signal and extract a first natural language text from the received first speech signal, in response to detecting that extraction of the first natural language text includes errors such that a request associated with the first speech signal is unprocessable, store the extracted first natural language text, receive, using the microphone, a second speech signal and extract a second natural language text different from the first natural language text from the received second speech signal, in response to detecting that the request is processable using the extracted second natural language text, detect whether a similarity between the first and second natural language texts is greater than a similarity threshold, and whether the second speech signal is received within a predetermined time duration of receiving the first speech signal, and when the similarity is greater than the similarity threshold, and when the first and second speech signals are received within the predetermined time duration, store the first natural language text in association with the second natural language text. a microphone; at least one processor; and a memory storing programming instructions executable by the at least one processor to cause the electronic device to: receive, using the microphone, a first speech signal and extract a first natural language text from the received first speech signal, in response to detecting that extraction of the first natural language text includes errors such that a request associated with the first speech signal is unprocessable, store the extracted first natural language text, receive, using the microphone, a second speech signal and extract a second natural language text different from the first natural language text from the received second speech signal, in response to detecting that the request is processable using the extracted second natural language text, detect whether a similarity between the first and second natural language texts is greater than a similarity threshold, and whether the second speech signal is received within a predetermined time duration of receiving the first speech signal, and when the similarity is greater than the similarity threshold, and when the first and second speech signals are received within the predetermined time duration, store the first natural language text in association with the second natural language text. receive, using the microphone, a first speech signal and extract a first natural language text from the received first speech signal, in response to detecting that extraction of the first natural language text includes errors such that a request associated with the first speech signal is unprocessable, store the extracted first natural language text, receive, using the microphone, a second speech signal and extract a second natural language text different from the first natural language text from the received second speech signal, in response to detecting that the request is processable using the extracted second natural language text, detect whether a similarity between the first and second natural language texts is greater than a similarity threshold, and whether the second speech signal is received within a predetermined time duration of receiving the first speech signal, and when the similarity is greater than the similarity threshold, and when the first and second speech signals are received within the predetermined time duration, store the first natural language text in association with the second natural language text.