After WordPad was killed last year, Microsoft paid a little bit of attention to Notepad by finally giving it a spell check ...

You can change the spell-check in Word into the languages you're learning with just a couple of clicks. Write your document and then switch on the spell-check to find the mistakes you made.

A linguistic difference could give the impression that the spell checker isn’t functioning properly. You might want to double-check what language Outlook is set to since it uses MS Word for writing.