Hi @Ranjan R Jinka,
Did you use OneNote for Windows?
OneNote sets the proofing language based on keyboard in Windows.
I suggest you try to install the OneNote program separately:
Then you can check if the language proofing can change successfully.
If the response is helpful, please click "Accept Answer" and upvote it.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.