Microsoft Windows 2000 was designed with multilanguage usage in mind. For example, the English version is capable of handling simultaneous input and output in languages ranging from Arabic to Vietnamese including Chinese, Japanese, Korean, Indic, and European languages in between. In addition, the user interface language can be easily changed without installing a new version of the product. The current release of the Mulituser Interface (MUI) offers twenty-three versions including European, Bidirectional, and Far East languages, all of which can be installed and selected as required at user level granularity. Such versatility is especially useful to those that are involved in Internationalization, Localization, and International QA as well as those that share the same machine but require different language settings. In this presentation, we look at MUI support from both the user and programmer's view. We explain the difference between system language and user language and show how an application can enumerate and query for available UI languages and load an appropriate user interface via multilingual resources or language DLL's.