Ready to learn a language that's out of this world? Duolingo, a free app that allows users to learn new languages almost like playing a game, is adding Klingon to its course list. The language, used ...

And yet, there is not, nor has there ever been, one definitive Klingon makeup design. Despite fan uproar practically every time a substantive change is made to the craggy foreheads and wispy beards of ...