A family of Microsoft word processing software products for creating web, email, and print documents.
The Language dialog has another quirk that may have been involved. If you change the "Do not check spelling or grammar" box but no language is selected in the list above it, the change won't be saved. For whatever reason, Word insists on having some language selected in addition to a change of the check box.
This gets to be a problem if you have individual words sprinkled throughout the document that are marked for a different language than the rest of the text. It means you can't use Ctrl+A to remove the "do not check" from the whole text without making the proofing language the same throughout the document at the same time.