"The Dothraki have no word for 'thank you.'" - Ser Jorah Mormont
Apparently, they have no word for "trousers" either.
I think it's fairly indisputable at this point that the central character in the telly adaptation of George R. R. Martin's Game of Thrones is, of course, Khal Drogo's arse. Played rather convincingly by Jason Momoa's arse, known mostly for its (aheh) supporting role in Stargate Atlantis.
It haunts my dreams.