Klingon, Elvish, Dothraki, and Nadsat: there are plenty of invented languages used in movies. But one of them, Interslavic, also has the potential to be useful to hundreds of millions of people. The language just made its film debut in a wartime drama, The Painted Bird, and its creator says it could be used by Slavic speakers from Siberia to Slovenia. h/t:(rferl)