6. A multilevel speech recognition method, the method comprising: determining, using a processor, whether a speech command of a user includes an application indication for an application by processing the speech command using an application speech recognition model, wherein the application speech recognition model is updated based on at least one of a voice, a pronunciation, or an accent of the user obtained from the speech command, and a word frequently received from the user included in speech commands, when the word is associated with the application indication; executing, at the processor, the application in response to the speech command being determined to include the application indication; and in response to the speech command being determined to not include the application indication, identifying a selected application selected by the user from a provided candidate application group of a category determined to be associated with the word using a category speech recognition model based on a set of words associated with the category, and executing the selected application selected from the provided candidate application group, the selected application providing a service associated with the speech command.
11. The method of claim 6 , wherein the determining comprises updating the selected application based on the updated application speech recognition model.