For development on pre-Windows Vista operating systems, language-specific resources for an application are either fully localized or not localized at all. Windows Vista introduces the concept of "partial localization," in which only some user interface resources are localized for a particular language. All resources that are not localized for this language are displayed in another language, called the "fallback" language. Partial localization is used in certain language versions of Windows Vista itself.
MUI technology allows the development of language-neutral applications that support partially localized languages when they run on Windows Vista. When creating such an application, you can decide the level of localization that you want by the way you place the user interface resource files. For more information on handling partially localized resources, see Placing and Loading Win32 Resource Files.
When a partially localized application is running, all resources that are not localized in the main user interface language displays in the fallback language. For example, Arabic-language resources for a particular application might be partially localized, using fully localized English as a fallback language. An even more partial resource set might be implemented for Persian, using Arabic as a fallback:
- Persian (fa)
- Arabic (ar)
- English (en)
- Arabic (ar)
Windows Vista is partially localized for some languages, and each user is able to use the regional and language options portion of the Control Panel to select a user interface language. A particular language offers a choice of up to four fallback languages. An application can obtain information about the fallback languages that are offered for a user interface language as described in Representing the Correct Language to the User. Most applications are not concerned with this information, as they can trust the resource loader to make appropriate selections using values previously selected in the Control Panel.