A data processing system and method for customizing a user output of a data processing system are disclosed. According to the method, a user preference for an audio or visual user output of a data processing system is determined. In response to determination of a user output having a first audio or visual frequency, the user output is mapped to a second audio or visual frequency in accordance with the user preference to obtain a customized user output. Thereafter, the customized user output is presented by the data processing system. In accordance with one embodiment, the user preference is determined by administering a test of the user's visual or aural acuity.