only noticed the warp trail and came to investigate. Improbably, the universal translator has been successfully used to interpret non-biological lifeform communication (in the Original Series episode "Metamorphosis"). In the Star Trek: The Next Generation (TNG) episode "The Ensigns of Command", the translator proved ineffective with the language of the Sheliaks, so the Federation had to depend on the aliens' interpretation of Earth languages. The TNG episode "Darmok" also illustrates another instance where the universal translator proves ineffective and unintelligible, because the Tamarian language is too deeply rooted in local metaphor. Unlike virtually every other form of Federation technology, universal translators almost never break down. A notable exception is in the Star Trek: Discovery episode "An Obol for Charon", where alien interference causes the translator to malfunction and translate crew speech and computer text into multiple languages at random, requiring Commander Saru's fluency in nearly one hundred languages to repair the problem. Although universal translators were clearly in widespread use during this era and Captain Kirk's time (inasmuch as the crew regularly communicated with species who could not conceivably have knowledge of Standard English), it is unclear where they were carried on personnel of that era. The episode "Metamorphosis" was the only time in which the device was actually seen. In the episode "Arena" the Metrons supply Captain Kirk and the Gorn commander with a Translator-Communicator, allowing conversation between them to be possible. During Kirk's era, they were also apparently less perfect in their translations into Klingon. In the sixth Star Trek film, the characters are seen relying on print books in order to communicate with a Klingon military ship, since Chekov said that the Klingons would recognize the use of a Translator. Actress Nichelle Nichols reportedly protested this scene, as she felt that Uhura, as communications officer during what was effectively a cold war, would be trained in fluent Klingon to aid in such situations. In that same movie during the trial scene of Kirk and McCoy before a Klingon judiciary, the Captain and the Doctor are holding communication devices while a Klingon (played by Todd Bryant) translates for them. The novelization of that movie provided a different reason for the use of books: sabotage by somebody working on the Starfleet side of the conspiracy uncovered by the crew in the story, but the novelization is not part of the Star Trek canon. By the 24th century, universal translators