In a multiscript environment, a locale can support more than one script, but only one locale can be set as current. An application creates a document in different scripts by tagging each separate script run (text in the same script). However, the current locale environment settings apply--for example, text is sorted according to the sorting rules of the current locale.
In the Chinese/Russian example above, rather than create two separate documents, the user creates one multiscript document containing both Chinese and Russian text. The cultural attributes of the active locale still apply--in the Chinese locale, the Chinese sorting rules apply to the mixed-script text.
In a Unicode locale, tagging script runs is not necessary because all language attributes are inherent in the Unicode codeset.