Consider the following scenario:
In Microsoft SharePoint Online, you browse to one of the following site collections:
My Site Host
OneDrive for Business personal site
You try to change the Default Language setting for the site collection by using the Language Settings option under Site Settings.
In this scenario, the setting isn't changed successfully.
To resolve this issue, enable the Multiple Language User Interface (MUI) for the affected site or sites. You can use the MUI feature to create sites in languages other than the default language for your SharePoint Online site or sites.
For more information about how to do this, go to the following Microsoft website:
Note: After you make this change, the UI for the affected site displays the language that you specified. However, on the OneDrive for Business personal site, the Shared with Everyone folder is not renamed. If you want this folder to use a name in the newly specified language, you must rename the folder by using the SharePoint Online UI.
This issue occurs because the default language for the My Site Host and Search Center site collections is defined by the following settings when you clicked the link to create the subscription:
The country that was selected on the office.microsoft.com page.
The language preference that’s specified by your browser settings.
For more information about multilingual features and about configuring your display language, go to the following Microsoft websites:
Still need help? Go to Microsoft Community.