Forum Discussion
Site language issue
Now I have been looking and surfing to the last page of the internet and the only thing I can find that might help you is this workaround. Hope this helps to solve your need.
https://blog.devoworx.net/2016/07/16/change-workflow-actions-language-in-sharepoint-designer/
Regards, Magnus
Jeyganesh correct, by design, you can never, ever change the language of your Office 365 tenant or any site once it is created. There are some uservoice requests to get this "feature" added. In my opinion, this is not a feature request, this is something that is broken. Language lock-in is not acceptable.
https://office365.uservoice.com/forums/273493-office-365-admin/suggestions/34841875-change-default-language-in-sharepoint-onedrive
https://sharepoint.uservoice.com/forums/329214-sites-and-collaboration/suggestions/30953740-change-the-default-language-after-the-sharepoint-s