You can change the system's display language in the Settings application.
Refer to this article to change the system language to another.
Devices with Android 8.0 and above
Navigate to Settings > System > Languages & input > Languages.
4. Select region.
After you add the language that you want, the display language is still the previous one.
To change display language, tap and hold the language line's icon() and drag it to the top of the list.