Hi John,
Thanks for posting in the community. We are happy to help you.
Regarding your query, I would like to reconfirm if you mean the shared mailbox in Outlook or a site mailbox.
If you mean the shared mailbox in Outlook, please try the following steps, then check if it meets your needs or not.
- Go to Outlook for Web
Go to www.office.com and click the Outlook icon
- Click your profile picture in the top right corner and click "Open another mailbox"
- Input the shared mailbox name and click "Open"
- Click Settings in the top right corner, select General> Language and time> change the language and tick the option "Rename default folders so their names match the specified language".
If the above steps don't meet your needs, please point it out and let us know. We look forward to your response. Thanks for your cooperation.
Sincerely,
George | Microsoft Community Moderator