The invented tongue of Klingon belongs to no man, corporation or star fleet, a society of language creators has told a federal judge as he weighs a copyright lawsuit against a fan-funded Star Trek film.

Last month Paramount and CBS filed a long list of complaints in federal court as part of its lawsuit against Axanar Productions, the creators of an unauthorized, crowdfunded Star Trek film, titled Axanar. The document includes dozens of complaints – gold shirts, Captain Kirk, triangular medals – but California judge R Gary Klausner was sent a petition from the Language Creation Society relating to one point in particular: the Klingon language.

Paramount’s attorney, David Grossman, quickly argued that it was “absurd” to say that Klingon, invented in 1984 for a film, exists as an independent language.

“A language is only useful if it can be used to communicate with people, and there are no Klingons with whom to communicate,” Grossman wrote in a brief.

But the Language Creation Society, a group of linguists and language inventors, filed a friend-of-the-court brief in support of the fans.

“Given that Paramount Pictures commissioned the creation of some of the language, it is understandable that Paramount might feel some sense of ownership over the creation,” wrote attorney Marc Randazza.

“But, feeling ownership and having ownership are not the same thing. The language has taken on a life of its own.”

Randazza argued that Klingon has escaped its creators thanks to the “thousands of people” who have made it “an actual living language”. Paramount could own a dictionary or dialogue from a script, he argued, but not a language used by Star Trek fans and others at conventions and colleges, in books and TV shows, and even during weddings.

“It would not take a Vulcan to explain their logic – even the Pakleds would know that nobody can ‘own’ a language,” Randazza wrote. Reaching back to the argument that no one can copyright a system of words, he called Paramount’s claim that no one speaks Klingon “absurd”.

“By their logic, ancient Greek is not ‘useful’ because the ancient Greeks are no longer with us, and the language has no native speakers, despite it being the original language of some of the seminal literary and philosophical works of the western world. Plaintiffs’ logic would seem to dictate that French is not ‘useful’ if spoken by a native German.”

Randazza used Klingon proverbs and translations to illustrate his point. He said that the translation of the Sesame Street song “Sunny day, chasing the clouds away”, for instance, is: “day of the daytime star, the clouds are filled with dread and forced to flee.”

“Klingon is not just a language,” he wrote. “It is a state of mind – and that state cannot be constrained by copyright law.”

Ultimately he called for the judge to dismiss Paramount’s claim to Klingon, and warned that if the film company had its way they would make thousands of people “serial copyright infringers”.

But invented languages can be copyrighted, others argue. Brad Newberg, an intellectual property lawyer who is not involved in the case, said that the invented languages of Star Trek, Game of Thrones and even the lexicon of Harry Potter are eligible for copyright.

Languages such as English or Spanish would not be copyrightable, he said, because they have no clear creator. That many Trekkies now speak Klingon doesn’t free the fictitious language from its original creator, he said – though if fans invented enough of their own words and grammar they might loosen the owner’s control. “You can get a real question of this might be copyrightable but who owns it, because there may be words in Klingon that were never created by the people from Star Trek.”

“Let’s say there were 2,000 words and now fans have created 10,000 words – that doesn’t mean all those words all of a sudden get owned by the original owner.”

He added: “Klingon as a whole is copyrightable, but that doesn’t mean that no one could use the Klingon language within a book or movie.” Newberg said that there was “a big spectrum” of infringement to fair use.

“If there’s some geek and he decides he’s only going to speak Klingon in high school, but he has nothing to do with the Star Trek universe, that’s probably going to be fair use.”