Abstract: In several non-English languages and cultures, such as Dutch and German, there is a formal and informal language form used to address a person. A device having a user interface is adapted for use with both formal and informal language. A user's preferred language form can change over time, and is determined directly or indirectly from characteristics of the user based on their use of the device, including how long the device has been used, a role of the user and/or his or her location. Another way of determining the characteristics of the user is to monitor the user's online behavior, including such data as social networking traffic, web sites visited, email and chat use, and the like. An application's user interface can be dynamically changed to use the current preferred language form.