Outlook How to change this list of languages

Hi Johannes,

Thank you for sharing the details of your concern.

The Dictionary language list in the spelling dialog is populated from the proofing dictionaries and language components recognized by the Office editor used in Classic Outlook. This is not a standalone customizable list, and Classic Outlook does not currently provide a supported option to manually add or remove individual entries directly from this dropdown.

If your goal is to control the language used to check spelling in an email, you can try the steps below:

1. Open a new email and select the message content.
2. Go to Review > Language > Set Proofing Language.
3. 
4. Select the preferred language.
5. Clear Detect language automatically, if enabled.
6. Select OK.

I also recommend checking the email signature, template, or copied content, as these items may retain their own proofing-language formatting.

For additional information, you may find these Microsoft articles helpful: Set up or change the languages used to check spelling and grammar

If the ability to manage individual languages in this dropdown is important to your workflow, you may consider submitting your feedback through the Outlook Community. This will allow your suggestion to be shared with the relevant product team for consideration.

I hope this information is helpful. Should you have any further questions or need additional assistance, please feel free to share them in the comment below. I'm very happy to help.  

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