[MicroStation CONNECT Ed. u13] _USTN_LOCALE_LANGUAGE

_USTN_LOCALE_LANGUAGE is a predefined and locked variable. According to recommendations I'm using this var to set some configuration issues. 

Now I have computers on which my config does not work as the variable points to 'de', although the application is started in english (en) (and no language pack is installed anymore, either).

Where does MicroStation draw the language from? I can't find _USTN_LOCALE_LANGUAGE set (as a definition) anywhere in the config, only as a reference.