Bork! Bork! Bork!
It works like any other language option in game, except that it doesn't have an associated spoken language for cinematics. Instead, English is used, but with Bork-subtitles. If you are in the European territory with this setting on, you are sent to the English districts; there are no Bork-districts.
This is the Hall of Heroes victory message in "Bork! Bork! Bork!". It is based on English but written out as if speaking with a deep Scandinavian accent.