What about the reverse: have they sued anyone over the use of just the language? Is it possibly defacto public domain?And it seems unlikely that anyone will spend thousands in legal fees to challenge the copyright so legal or not, they have a defacto copyright.
Who came up with the language anyway? I'd be surprised if it was Paramount. Obviously they invented the concept and a lot of the key vocabulary, but I doubt they had anything to do with producing the Klingon Shakespeare translations, etc.