Foreign Film Dub was a game played on the British and American editions of Whose Line.
Two performers (or, early on in the American edition, one performer and Drew Carey) would perform a scene from a film, with the title and language determined by the audience. The other two performers would "dub" the film into English, creating situations to which the "actors" had to respond.
Generally, the humour was derived from the dubbing process - with long monologues translating as "yes" or "no", and physical actions being misinterpreted. Occasionally, the language itself proved inherently funny, with Ryan Stiles often sounding suspiciously like the Swedish Chef from the Muppets.
On a number of renditions of the game, the language suggested was not a real language, which didn't stop anyone. One American rendition featured a film performed in "Canadian", which led to a number of jokes at Canada's expense.