Hello,
the localization of the World Editor other than enUS does not work properly. It can be seen in the game files that World Editor-specific locale files do get downloaded when selecting another language in the Launcher and these do get used when running the World Editor, but almost all of the strings in those files are identical to enUS.
Most of the things that exist today in the World Editor had a translation before Reforged. Now almost all of those translations are not used anymore and the language is inconsistent when a small part is actually translated. So this clearly appears to be a bug and it seems like the language pack is wrongly assembled (Does it somehow use the enUS variant of the files as a base and try to incrementally merge it with non-enUS contents in order to make the non-enUS variants of the files?).