1. A multilevel speech recognition method, the method comprising: extracting a keyword from a first speech command received from a user; determining whether the extracted keyword from the first speech command of the user includes an application indication for an application using an application speech recognition model; in response to the extracted keyword from the first speech command being determined to not include the application indication, providing a candidate application group of a category providing a service determined to be associated with the extracted keyword, and identifying a selected application selected by the user from the provided candidate application group using a category speech recognition model based on a set of words associated with the category; and processing a second speech command, from the user, for the selected application selected from the provided candidate application group, using the application speech recognition model, based on a set of words associated with the selected application, 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 second speech command, and a word frequently received from the user included in the second speech command, the word being associated with the selected application.