Configuring Language & Region preferences for a language other than English doesn't change the language of folders in other macOS user accounts. User accounts don't have access to the language settings or home folders of other user accounts, so English names are used by default when viewed from the other account. This doesn't apply to shared folders.
In this example, the contents of accounts named apple and orange are shown while logged in as apple. Notice that the Desktop, Documents, Downloads, Library, Movies, Music, and Picture folders of the orange account are in English regardless of what apple or orange has chosen in Language & Region preferences.