Microsoft 365 - Language confusion
Short description:
In Microsoft 365, there are many different language settings at the tenant level, for users, in Exchange, teams, etc. Incorrect combinations lead to unexpected interfaces, system messages or support requests.
1. Tenant settings
- When creating your tenant, you need to choose a location (region). This will determine your tenant preferred language.
- The tenant-preferred language is the standard language for newly created cloud users. Changes to an unsupported language are often not possible, in some cases a new tenant would have to be created.
2. Azure AD / user attributes
- UsageLocation: Specifies which region a user is sitting in. Relevant e.g. B. for licensing or language assignment.
- PreferredLanguage: Used for many services (e.g. B. SharePoint, OneDrive, web apps) to determine the user's display and interface language. If this attribute is empty, the tenant standard applies.

3. Exchange/inbox regional settings
- Exchange has its own mailbox regional configuration (language, date format, time zone).
- When a new mailbox logs in for the first time, this language setting is often automatically removed from the client (e.g. B. Outlook) adopted.
- You can reset regional settings and folder names with the PowerShell cmdletSet-MailboxRegionalConfiguration. .
4. Hybrid / on-prerem AD synchronization
- In hybrid environments, this is usuallyOn-premises ADUsed as source.
- You should make sure that thec- Attribute or other country identifiers in the on-premises AD are sensibly maintained and withUsageLocationsync to Azure AD.
- That tooPreferredLanguageAttribute should optionally. sync or filled so that users do not see in the wrong language.
5. Microsoft 365 groups / teams etc.
- When a Microsoft 365 group is created (with Teams/SharePoint), SharePoint & Site use the language of the Tenant Preferred Language.
- The Mailbox language for the Mailbox groups is based on the language of the creator or mailbox.
- When cloning / creating via graph API, it is currently not possible to set a language other than the tenant language.

6. Teams / client language behavior
- The language of the team client depends on the operating system or client settings. The admin cannot control this centrally, the user changes them manually in the settings.
- Meeting invitations: When you schedule meetings in teams, the language is used based on your client; Outlook-based invitations have the language of the mailbox.
- Teams notifications (in the absence, group access, etc.) often have the language of the tenant default or user, depending on the scenario. (Not every notification uses thisPreferredLanguageattribute.)
7. Conclusion & recommendations
Many dependencies and overlaps, not all settings can be centrally controlled.
The main screws you should check and maintain:
- PreferredLanguage (in Azure AD / On-Premite AD)
- UsageLocation
- Mailbox regional / language settings in Exchange
If these three are properly maintained, you've already taken a big step towards ensuring a consistent user experience.
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