1. Open any Microsoft Office software. For Outlook, you have to be composing a new email or replying to an email to see this ribbon.
2. Go to the Review tab and click on Language.
3. Click 'Set Proofing Language'.
4. Click on your desired language to highlight it in blue, and click on 'Set as Default'.
5. A prompt will pop up. Select Yes.
7. Click OK.
8. Press the Windows icon on your keyboard to open up the Start Menu. Type in 'keyboard' and click on 'Language settings'.
9. Check if your Windows display language is set to the same language as selected in step 4.
If your language does not exist in the Windows display language's drop-down menu, you will have to add it. Click on 'Add a language' and select that language you need. Click Next, then Install.
All done! Your spelling proofing should now work as intended.