This article explains how to change the display and/or editing language in Word for Office 365, Word 2019, Word 2016, Word 2013, Word 2010, Word Online, and Word for Mac. On Windows, but not on macOS, you can choose them independently of the language installed for your operating system.
How to Change the Language in Microsoft Word Back to English
The display language in Word controls the ribbon, buttons, tabs, and other controls. To force a display language in Word that is different from that of your operating system:
Select File > Options.
In the Word Options dialog box, select Language.
