Hi @JD
Teams tag is mainly focused on the general issue of Microsoft Teams troubleshooting. According to your description, your question is not in our support scope.The following suggestion is just for your reference:
If you want to set a preferred language for a user, you can use PowerShell in Azure Active Directory or on-premises Active Directory to set a preferred language for a user. For more information, see:How to set language and region settings for Microsoft 365 or Office 365.
If you want to Change the system language for everyone in your organization:
Sign in with your global administrator account at https://portal.office.com/adminportal/home.
Step1.In the Microsoft 365 admin center, choose Settings > Org settings > Organization profile.
Step2.Choose Organization information.
Step3.Select a language from the Preferred language list for everyone in your organization.
Step4.Choose Save.
For more details, see:https://learn.microsoft.com/en-us/microsoftteams/change-the-default-language-for-greetings-and-emails
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