Conveniently Precise Translation

"Traduttore, Traditore "Translator, Traitor" in self-disproving Italian."

There's a phrase that's important to the plot or arc (possibly Arc Words). There will come a time the characters encounter the phrase in a foreign language. The foreign phrase will always be translated precisely to the important phrase, even though linguistic quirks would make this unlikely.

However, in TV land, languages have exact 1:1 word/syntax relationships and the translation, even if done by a third party who has never heard the Arc Words, will always be exact.

An ancient inscription will always be rendered in complex long words with nuanced meanings, despite the fact that on-the-spot translation typically sounds more like a two year old trying to put together a sentence.

It gets even more amazing when ancient spells and prophecies rhyme or are puns in English.

For a good real-world demonstration, see Lost In Translation.

An exception occasionally pops up when the form of a word in another language (usually with declensions, like Latin) reveals information such as number or gender that would require additional words in English, allowing the translation to be more precise than one would expect.

See Either World Domination or Something About Bananas for the most common subversion, and Lucky Translation for a few real life examples.

Anime and Manga

 * Averted in Magical Girl Lyrical Nanoha with Carim's prophecies. They foretell the future exactly as it will come to pass... except you can't pick what is predicted and it comes out in ancient Belkian, which is apparently very difficult to translate properly. The accuracy is therefore reduced to the level of 'educated guess' or 'accurate horoscope.'
 * The difficulty isn't so much the fact that they're in Ancient Belkan, but that they're in poetic verse.

Comic Books

 * In a comic in French translated from Italian, Mickey and some professor can't understand a message let by an ancient civilization. But Dingo (Goofy), who like games, say it's just a rebus. The trope is then played for laugh when he say the rebus is "in Italian... for some reason", and translate it saying things like "that's a drawing meaning it's little, piccolo in Italian"...

Film

 * In Titanic, we've been told the necklace is called "The Heart of the Ocean." Later when Cal presents the necklace to Rose, he calls it "Le Cœur de la Mer," which both characters simultaneously translate as "The Heart of the Ocean." However, one would usually translate mer as "sea."
 * Of course, if it's a well-known necklace it probably has an official translated name in English, which both characters probably already know. (Compare how everyone "knows" that the "real" translation of the Chinese "Honglou Meng" is "Dream of the Red Chamber" rather than "Red Room Dreams" or "Scarlet Quarters Reverie".)
 * The treasure map in The Goonies is in Spanish, but when translated into English, it becomes rhyming verse. No one even stops to consider how unusual this is.
 * Subverted in The Usual Suspects: a Hungarian who encountered Keyser Soze is translated by an American interpreter as saying that they picked up a pasas, or "package." In reality,
 * The movie Stargate had Daniel Jackson correct a translation of Ancient Egyptian hieroglyphs, changing "door to heavens" to "Stargate". This is possibly because "Stargate" sounds cooler than "door to heavens". However in the SG-1 episode Moebius Jackson travels back in time and helps plan the uprising that would lead to the stargate being buried along with the coverstone with the hieroglyphs (which we can assume he helped write) which he would 6000 years later translate as being Stargate. So it's not suprising he can translate it as he wrote it.
 * Lightly spoofed and subverted in Stargate SG-1, where Dr. Jackson (now the team linguist) once translated something as "the place of our legacy" but expressed some doubt by adding that it could also mean "a piece of our leg, but the first seems to make more sense."
 * This was done again when SG-1 was searching for the Lost City. Jonas Quinn thought that it should be translated as the City of the Lost because the Ancients couldn't possibly lose one of their own cities and of course, Jack O'Neill took this to mean the City of the Dead. They came full circle when Dr. Jackson returned to the team and revealed that the city had been built lost and was therefore the Lost City.
 * Subverted in Event Horizon. The distress signal sent by the titular starship contains the Latin phrase liberate me ("save me"). It was later realized that the message was actually liberate tutame ex inferis ("save yourself from Hell").
 * Amusingly enough, the translation was still a little off. It would more accurately mean "free me/yourself."
 * Atlantis: The Lost Empire plays with this. Reason why Atlantis was never found was a single error: instead of Írland, it was supposed to be Ísland. Which, conveniently are Ireland and Iceland in English...(for added fun, they also translate into Irlanti and Islanti in Finnish, keeping the joke).

Literature

 * That is not dead which can eternal lie, and with strange aeons even death may die
 * Which, though poetic, is odd when considering the original was supposedly written in Arabic. Given that the English translation of the book is said to have been contemporaneous to the King James Bible, one might attribute it to a poetic translator.
 * The Call of Cthulhu RPG makes a deliberate point of this: with each successive translation of the Necronomicon (or any other Tome of Eldritch Lore ), its in-game usefulness as a source of knowledge/power/danger decreases.
 * One RPG sourcebook contains a chapter that attempts to explain things like this from an in universe perspective. Its Arabic version of the above quote also rhymes, and actually explains more than the English version.
 * Played with in The Book of the New Sun: Terminus Est, the name of an important execution sword, never receives a single official translation. It's rendered once as this is the line of division and once as this is the place of parting. Both translators ignore the most obvious choice:this is the end.
 * JRR Tolkien's Middle-earth is not a case of the trope, as his Constructed Languages and their texts are not literal 1:1 translations. There are other-language poems with their 'Westron'/English translation both given by Tolkien, who are visibly not 'identical' but treated like any real-world poetry translation to produce a text both meaningful and working within the respective aesthetical rules. Both instances/reminders in the narrative text as well as in additional texts provide more insight into both in-universe and the (pretend) 'Westron-to-English' language and translation issues and problems.
 * A in-universe trope subversion showing an on-the-spot translation occurs in The Lord of the Rings: Gandalf translates the (punctuation-less) inscription on the door to Moria (Pedo mellon a minno) as "Speak, friend, and enter." which, while 1:1 correct, should have rather been rendered as "Say 'friend' and enter." to preserve the meaning: Saying aloud the Sindarin word 'friend' (mellon) is the password to open the door.
 * This is averted in Eragon. Brom translates a poem from the Ancient Language (Elvish) for Eragon, which sounds pretty but has no real rhyme or meter, and Brom says himself that he can't translate it perfectly. And therefore makes perfect sense. Again averted in the sequel, Eldest, when Eragon composes a poem in the Ancient Language. We're shown a translation of it, and it doesn't rhyme either. This allows the author to provide incredibly beautiful, classic poems without having to write overwhelmingly movie poems fromscratch.
 * The novel Trixie Belden and the Mystery of the Blinking Eye features a prophecy written by a Spanish-speaking woman, in Spanish, which is then translated into English. Amazingly, it was written so precisely that it rhymes perfectly in English, and although it becomes a plot point that they aren't sure whether a line ought to read "big headed man" (as in, a man with a physically large head) or "big-headed man" (as in, a man who thinks a lot of himself), this is only an artifact of the English translation, and no such confusion could have existed in the original wording.
 * In the first Artemis Fowl book, the titular character is able to write a computer program that is able to decipher a written language that predates Egyptian hieroglyphics, and then translate it into English in perfect meter and rhyme. All this without actually having any knowledge of other languages himself. Sure he's supposed to be a genius, but...
 * Then again, Gnommish is less an ancient language and more a fancy English cipher.
 * A poem in the final Deverry book includes a note that it rhymes in Deverrian, but not English.
 * Averted in the StarWars novel Traitor: Nom Anor (A Yuuzhan Vong who speaks Basic, i.e. English), while listening to an excruciatingly boring shaper's drone, muses (apparently in Basic) that "maybe that's why we call them drones". He decides not to share this with anyone, because it's only a joke in Basic. (And a really weak one at that.)

Live Action TV
"Dax: Given the tone of the rest of the inscriptions, I would bet on the horrible suffering."
 * Subversion: In Buffy the Vampire Slayer the Arc Words in Season 7 are "From beneath you, it devours". Andrew and Jonathan reveal in "Conversations With Dead People" that, while in Mexico, they've had dreams with the refrain "Desde abajo te devora." Andrew translates the phrase as "It eats you, starting with your bottom". The literal translation is "From below, it devours you", but this particular phrase probably would translate fairly closely to Spanish and back.
 * Andrew provides his own lampshade a little earlier in the scene when he complains that Klingon was easier to learn than Spanish because the former "had much clearer rules on transitive and intransitive verbs."
 * Used twice in Angel: The so-called Shanshu Prophecy says that the vampire with a soul will "shanshu" as a reward if he makes it through his trials. Wesley struggles with finding a translation for this word, first going for, but finally discovering that.
 * Also spoofed in an episode where Lorne states that a group of demons "...either are going to discuss it with the prince, or go eat a cheesemonkey".
 * Frequently used in The Twilight Zone, notably in the episode "To Serve Man", which manages to simultaneously subvert this trope and provide one of the most ridiculous examples of it. Translators translate the name of the aliens' book as "To Serve Man" but don't realize until later that the "serve" in this case means to . However, the entire premise of this misunderstanding of the translation is patently ridiculous, as it asks the viewer to seriously believe that the exact same pun exists in two completely unrelated languages.
 * The original Damon Knight short story that the episode was adapted from does attempt to get around this by saying that English and Kanamit share certain linguistic quirks and double meanings. (It also depicts the translation as less like codebreaking than the TZ episode; the people in the story use a Kanamit-English phrasebook as a starting point for the translation.)
 * To get slightly geeky on the subject - it's not that unlikely in any language with transitivity distinction, as the two senses of "serve" describe the same action with different object focus "to serve food (to Man)" and "to serve Man (some food)". I wouldn't be surprised to find similar ambiguity in most languages (at least, on Earth...)
 * It's a bit more complicated, as you need the words "to give food" and "to do favors" to be alike, which is reasonably rare and that the dative and accusative forms of 'man' to be alike.
 * Well-spoofed in a Simpsons Treehouse of Horror episode where the Simpsons are kidnapped by Kang and Kodos and fed well... Lisa becomes suspicious and finds a dusty tome titled 'How to Cook Humans.' She publicly confronts the aliens in front of her family. Kodos takes the book and blows off some dust. The title is revealed as 'How to Cook For Humans.' Lisa claims that there is more 'space dust' on that cover and blows more of it off. The book's title changes to 'How to Cook Forty Humans.' Naturally, the alien wrenches the book from her hands for the last time and blows as hard as he can. The official title for this thing stands at 'How to Cook for Forty Humans'. The aliens are dismayed at humanity's suspicious nature and claim they would've offered paradise... They also express disgust at the sheer quantity eaten. Their alien chef cries. It also lampshades the fact that the book is in English by saying that by an amazing coincidence, English and Rigilian are exactly the same. Great episode.
 * Subversion on Deep Space Nine: Dax translates a particular line of ancient Bajoran glyphs as meaning that the people will either "suffer horribly" or "eat fruit", depending on context.


 * A related instance occurred in the pilot episode of Lost. Shannon translates the French distress call as "It killed them all." However, the actual pronoun used is "il," which would more commonly be translated as "he." Hence, she more likely would translate the message as "He killed them all." However, seeing as some thing had just killed the pilot, the line needed to be translated with "it."
 * The Star Trek: The Next Generation Episode "Darmok" gleefully deconstructed this trope. When trying to communicate with an alien race, the universal translator didn't work on their language because their speech patterns were vastly different. Their language was based on metaphor, "Darmok and Jalad at Tanagra" is said repeatedly to the Enterprise crew, but it isn't learned until much later that they learn Darmok and Jalad were mythological heroes who became friends at the place Tanagra, slaying a legendary beast. So when they say "Darmok and Jalad at Tanagra" it is a term for a friendship formed while battling a common foe.
 * Another example is the phrase "Sokath. His eyes uncovered!" which is taken to mean "He understands!"
 * The Star Trek: Voyager episode "Riddles" features Neelix telling a joke to Tuvok. The riddle is, essentially, "Some guy is stranded on a desert island with only a calendar, isn't rescued for six months, but survives. How did he do it?" Tuvok is rather unimpressed at the answer of, "He ate the dates." Later, Tuvok proposes that "He ate the Sundays (sundaes)" could be an alternate answer. These are, mind you, alien characters and neither one has any incentive to learn English since they live with universal translators. Neelix in particular was only exposed to humans (and therefore English) seven years ago. The implication is either that both these characters took the time to learn English for some reason, and the joke wasn't Lost in Translation, or dates/sundaes are both food- and time-related words in three different languages.
 * Tuvok, at least, has the excuse of being readily familiar with the Earth dating system. It's not unreasonable to expect Vulcans to have studied English, either, as it is occasionally stated to actually be the official language of the Federation, not just a Translation Convention. As for Neelix, he could have simply looked the joke up, and he is sometimes portrayed as quite enthusiastic about studying the cultures of his new friends. (E.g. preparing Klingon food for a holiday B'Elanna doesn't even bother to celebrate.)
 * The original Star Trek had an example similar to the Zeitgeist one below where the Enterprise runs into a planet of space Romans where the rebels worship the sun. It is revealed at the end that it's actually the "son of God", even though all the words are being spoken through a universal translator.

Video Games

 * There's a moment in Metal Gear Solid 4 where Snake reads out the slogan of the French PMC "Pieuvre Armament" as "Arms of the octopus. Arms for your war." This is a reasonably okay slogan for a PMC named after an octopus, until you realise the slogan was originally in French, and he was translating from that - the appendages/weapons double meaning for the word 'arms' doesn't exist in the original slogan, which uses the words 'tentacles' and 'armaments'. With the wordplay gone, the supposedly catchy slogan loses a lot of advertising power.
 * Unless the founders intended it as a Bilingual Bonus.

Web Original

 * In the Zeitgeist movie, which contains many research errors, one theory brought forth is that Jesus Christ is a ripoff from earlier sun gods. See, he's the son of God, which sounds similar to sun, get it?