You can change your language in Budgie by opening the Budgie Menu and then clicking on "Region and Language" in the System Settings category.
You will now be shown the following window. This window allows you to change your language, formatting for dates and times and the language of your keyboard.
If your language does not appear in the list, click the ⋮ button at the bottom (three vertical dots) to show all the available languages. You can use the search box to go directly to your choice or scroll down the list.
With GNOME, open the Overlay using the `Super` button on your keyboard or by clicking the applications icon in the dock and then find and click on "Region and Language".
You will now be shown the following window. This window allows you to change your language, formatting for dates and times and the language of your keyboard.
If your language does not appear in the list, click the ⋮ button at the bottom (three vertical dots) to show all the available languages. You can use the search box to go directly to your choice or scroll down the list.