Marc Okrand is an American linguist best known for creating the Klingon language for the Star Trek franchise. He developed the language in the 1980s, expanding its vocabulary and grammar to make it a fully functional language used by fans and in various media. In addition to his work on Klingon, Okrand has contributed to other fictional languages, including Atlantean for the animated film Atlantis: The Lost Empire. He has also worked as a consultant for various films, helping to create realistic languages and dialects for characters.