What does it mean by microsoft windows (english) why not UK for my display language?

In the "Office display language" box, the first row "1. Match Microsoft Windows [English] <preferred>" means that Office is using the same language that's currently selected as the Windows display language. That is actually English (United States). [Microsoft tends to be US-centric in labeling, so "English" assumes English (United States).] Note that neither of these selections has anything to do with the Office proofing language in the second box of the dialog.

You can tell whether the Office display language is UK or US by opening the dropdown for the font colour to see whether the labels say "colour" or "color".

You can change the Windows display language to English (United Kingdom) in the Windows Settings at Time & Language > Language & Region > Add a language. After you do that, you'll probably have to change the setting in Office to match the new Windows display language.

Alternatively, you can change only the Office display language so it ignores the Windows display language. In Word's Options > Language dialog that you showed, click the Add a Language button and select "English (United Kingdom)". There's a checkbox that says you can make the added language the preferred language; leave that checked. Office will download an update package and install it. Then you should see English (United Kingdom) as the preferred display language, and your "colour" labels will look correct.

Dear @Alan Lopez,

Thank you for posting your question in the Microsoft Q&A forum.

The option “Match Microsoft Windows [English]” means that Office will use the same display language as your Windows operating system. If your Windows is set to English (United States), the Office interface such as menus and buttons will appear in U.S. English. This setting only affects the interface language, not the content of your documents.

It means this does not change how your documents are checked. Since you already have English (United Kingdom) set for proofing, so spelling and grammar will follow UK rules, for example using “colour” instead of “color”. Your work will not be affected. The only difference you will notice is in the wording of the interface, such as “Color” in menus rather than “Colour,” but all features and functionality remain the same.

If you prefer the Office interface to appear in UK English, you can either change your Windows display language to English (United Kingdom)

• Settings > Time & Language > Language & Region > Add a Language > Choose English (United Kingdom) > Next > Check "Set as my Windows display language"
• In Office, go to File > Options > Language > add English (United Kingdom) and set as a display language or choose English (United Kingdom) as set as preferred instead of “Match Microsoft Windows.”

I hope this information is helpful. If I misunderstand anything, please feel free to reach out.

Please understand that our initial response does not always resolve the issue immediately. However, with your help and more detailed information, we can work together to find a solution.

Thank you for your patience and your understanding. If you have any questions, please feel free to reach out.

I'm looking forward for your reply.

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What does it mean by microsoft windows (english) why not UK for my display language?

As was stated in your earlier post, a display language is what is used to display text for the graphical user interface (e.g., menus, ribbons, etc.). The reason it is not showing English UK is because it wasn't selected when the installation occurred. You can select English UK by following Jay's advice.

Will this affect my work

No, it affects only the graphical user interface. Your "work" is affected by what authoring or proofing language you choose.