The stupidity of Power Point itself and all those fucks with "I'm working for Microsoft" tattooed on their foreheads is simply beyond imagination. You actually cannot change language of all PowerPoint slides at once. You have to:
- do this manually (each and every slide and text box separately!),
- mess up with outline view (won't work for future-written text!),
- mess up with system settings or
- even be forced to use Visual Basic for Applications (here, here, here and here).
Thirty years of PowerPoint's development wasn't enough time for MS-Morons to figure out that global change of language would actually be a useful functionality!
wow I hate them...