I love the fact that I can simply switch the language in Revit by simply having two different desktop shortcuts with appropriate language codes.
But if you combine this with some IFC-testing, you may end up with quite some mess in your IFC Export Options file because your Revit categories will be listed in multiple languages and pressing „Standard“ won’t solve the problem.
There is a little trick however which you can use to reset the export settings completely: delete the file shown in the header of the options dialog box and THEN click Standard. This willl re-generate the settings for your current Revit-language:
German 
English