11. A speech recognition method comprising: obtaining a derived word of a designated search target word, the derived word being generated in accordance with a derived word generation rule stored in a second memory section or read out from the second memory section where the derived word is stored in association with the search target word; setting, by a processor, the derived word by the obtaining to an outputting object or a rejecting object according to setting designation information or a user's instruction, the setting designation information being stored in the second memory section and indicating whether the derived word is the outputting object or the rejecting object; searching, by speech recognition, audio data stored in a first memory section to extract word-spoken portions where the search target word and the derived word are each spoken, the derived word being obtained by the obtaining and set to the outputting object or the rejecting object by the setting; rejecting, of the word-spoken portions extracted by the searching, the word-spoken portion for the derived word that has been set to the rejecting object, and outputting the word-spoken portion extracted by the searching and not rejected by the rejecting, wherein the derived word generation rule is generated based on a difference between the search target word and a derived word that is stored in the second memory.
11. A speech recognition method comprising: obtaining a derived word of a designated search target word, the derived word being generated in accordance with a derived word generation rule stored in a second memory section or read out from the second memory section where the derived word is stored in association with the search target word; setting, by a processor, the derived word by the obtaining to an outputting object or a rejecting object according to setting designation information or a user's instruction, the setting designation information being stored in the second memory section and indicating whether the derived word is the outputting object or the rejecting object; searching, by speech recognition, audio data stored in a first memory section to extract word-spoken portions where the search target word and the derived word are each spoken, the derived word being obtained by the obtaining and set to the outputting object or the rejecting object by the setting; rejecting, of the word-spoken portions extracted by the searching, the word-spoken portion for the derived word that has been set to the rejecting object, and outputting the word-spoken portion extracted by the searching and not rejected by the rejecting, wherein the derived word generation rule is generated based on a difference between the search target word and a derived word that is stored in the second memory. 12. The method according to claim 11 , wherein the second memory section stores the setting designation information by the derived word generation rule or by the derived word stored in the second memory section, and wherein the obtaining sets the derived word to the outputting object or the rejecting object based on the setting designation information that is stored in the second memory section and corresponds to the derived word by the obtaining.