Follow the below steps to Enable/ Disable languages in CRM Online,
Step 1: Goto Dynamics 365 -> Settings -> Administration. Click on Languages.
Step 2: Select the required Language to Enable/ Disable and Apply.
In this Example, I am going to Enable Language Hindi (India).
Step 3: Click on Ok to Confirm Language Change.
Step 4: It will take some time to Enable/ Disable Languages.
Step 5: Click on Personal Settings to see the Enable/ Disable Language changes.
Step 6: Go to Languages Tab and see the newly added language. Select Hindi (India) to see the changes in CRM and click on OK.
Step 7: You can see the new language in CRM.
Hope you learned a new thing today :):):)