How to change the language of an entire Powerpoint

I tend to do a bit more Powerpoint that I would like to.

Today, I had to translate one. So to get correct spelling checks, I wanted to modify the Proofing language.

That's how to do it:
  1. Open the Outline view
  2. Select all the text in the view
  3. Go to the Review tab
  4. Select Language -> Set Proofing Language
  5. Now select any language you like. It will be applied to the entire document
Yes, I promess, the next entry will be more technical.