Originally there was no Klingon dialogue in The Motion Picture
Klingon dialogue was not originally used in The Motion Picture
Called Klingonese in the Star Trek: The Original Series episode, “The Trouble with Tribbles,” the Klingon language was never spoken on screen until it made her debut in the 1979 film, Star Trek: The Motion Picture. And, originally, it was not said in this movie either.
When The Motion Picture was in production, the actors who played the Klingons said their lines of dialogue in English. It was only after recording the scenes that it was decided that the dialogue should be in Klingon. James Doohan (who played Commander “Scotty” Montgomery Scott), who had an ear for languages and dialects, as well as associate producer, Jon Povill, took on the challenge of creating the words which were then spoken by players. And it was much more of a challenge than fans ever imagined, as Doohan and Povill had to come up with words that would match the actors’ existing lip movements, so the lines just had to be doubled and not refilmed.
And then the Klingon language continued
Although Doohan started the language, linguist Dr. Marc Okrand developed it. Actor Mark Lenard, who played Spock’s father Sarek, made sure that Dr Okrand knew who had created the first lines of the Klingon language, and before Okrand, Lauren Weinstein, who worked in the effects department for The Motion Picture, was tasked with creating a language written in Klingon.
Klingons were fluent in English on Star Trek series and in movies, but the addition of a language they can call their own added to their originality. It is certainly a difficult language to speak, even though thousands and thousands of people are still trying to learn it. In fact, so many people wanted to learn the language, Duolingo started to offer free training in 2018 which continues to this day.