The add-in will select all text objects in the presentation and change the proofing language to
Download the SetProofingLanguageAddIn.ppam file and save it to %USERPROFILE%\AppData\Roaming\Microsoft\AddIns
I have no idea. Suggestions?
Go to Add-ins, select the language and click Set Proofing Language.
If you work in international environments, trying to spell-check a PowerPoint presentation is a nightmare - PowerPoint doesn't have a way to select EVERY text in the presentation - this includes smart shapes, text boxes, titles, tables etc Using "slide sorter" does not work either, at least for me.
This is quick hack, be sure to try out first in a copy of a document. Use it at your own risk.