Dear Philipp Oberberger,
Greetings! Thank you for posting in Microsoft Community. We are happy to help you.
Per your description, I understand you want to change Word Online language to English.
I'd like to help you, we can work together to narrow down and resolve the situation.
Please kindly note that all the Office apps files are saved in OneDrive and the OneDrive display language is completely independent from the Microsoft 365 display language.
May I know if your OneDrive language is English? If not, you may try steps below:
- Open the OneDrive by clicking on the app launcher from the Microsoft 365 home page > select OneDrive
- Once on the OneDrive page > click the Settings icon (gear icon) from upper-right corner, click OneDrive Settings
- On the OneDrive Settings page, click Return to Classic OneDrive page from the bottom left.
- This will take you to the OneDrive classic version > from there click on the gear setting on top right navigation bar > select the site settings > then click on the language settings from Site Administration.
- From there enable the multiple language toggle, choose English, and Save.
Note: It may take up to 24 hours to take effect. You may need to sign out from Microsoft 365 and then sign in to check if Word Online changes to English.
However, if your OneDrive language is already set to English, your Word Online is still not English, I deeply understand the inconvenience caused and apologize for it.
Let me help you further. May I know if Excel Online and PowerPoint Online language is English?
Thanks for your time and cooperation! We hope you stay safe and healthy always.
Sincerely,
Tina | Microsoft Community Moderator