A great way to add depth and character to an alien race, especially antagonists, is to give them their own language, and have them use it often. Frequently, one phrase will be repeated over and over again by characters speaking this language, but for some reason, won't be translated for the viewer, leaving you to wonder exactly what this alien phrase means, and why they say it so often.
If a work goes on for long enough, expect that the meaning of the phrase will eventually be explained. This may be done to add yet more depth to aliens and their language, to get the fans to stop pestering everyone involved in the production with questions about what it means, or for the sake of a good joke (or a bad joke).
Inverse of You Are the Translated Foreign Word. Compare Reality Has No Subtitles, where foreign languages remain untranslated, usually because the point-of-view characters don't speak them. Compare Pardon My Klingon, when words or phrases aren't translated due to vulgarity.
- During the 1980s, the Audi car marque ran a memetic series of TV and press adverts in the UK whose tagline was "Vorsprung durch Technik... as they say in Germany." The meaning was never explained in the adverts — it actually means "progress through technology", and had been used by the brand for much longer in Germany itself.
- The Transformers: The Movie: The universal greeting "Bah-weep-Graaaaagnah wheep ni ni bong", which was never given an English translation in the film.
- The Lord of the Rings: Gimli's recurring Khudzul Battlecry Baruk Khazad! Khazad ai-enu! is translated in the appendices as "Axes of the Dwarves! The Dwarves are upon you!"
- In A Song of Ice and Fire, after Arya learns the Valyrian phrase Valar morghulis from an assassin, she adds it to her "prayer list" of people she intends to kill and says it when she kills a guard escaping from Harrenhal. It's not until she goes to Braavos that she learns that it means "All men must die."
- Star Trek Rihannsu: The Romulan word mnhei'sahe. It's variously translated as "luck," "love," and "The Ruling Passion," but none of these are entirely adequate. It's less a word than it is a name for the Romulans' Blue-and-Orange Morality, and if you were to truly understand it, you would truly understand the Rihannsu.
Ael: [to her crew on the intercom] Honor to you, and mnhei'sahe.
[Kirk looks confused]
Ael: I wished them luck.
Kirk: I thought that word meant "love."
Ael: What's the use in a word that can only mean one thing? Besides, in this context, they're close enough.
- Abraham Setrakian from The Strain spouts a phrase (which is not printed) in his native Romanian before dispatching vampires. He later says it means "My sword sings of silver", but it sounds better in the old language. Eph later says it in English when he tries to kill The Master.
- The Thrawn Trilogy: Leia is the Mal'ary'ush. The Noghri who recognizes her as such immediately clarifies, saying that she is the daughter and heir of the Lord Darth Vader. Later it's clarified further to mean that she is heir to his authority and power. Supplemental material reveals that the word actually means "Heir of the Savior".
- Babylon 5: Comedy duo Rebo and Zooty, played by Penn & Teller, Zooty (Teller) only speaks through "his machine," which makes a variety of funny noises and voices, including his Catchphrase, "Zooty, Zoot-Zoot!" It's never revealed to the audience what it means, if it means anything. Sheridan and Londo once have a long argument about whether or not it's even funny.
- Doctor Who: The Sontarans are prone to breaking out into chants of "Sontar ha!" Given an Ironic Echo at the climax of "The Poison Sky" when Rattigan shouts the phrase at them sarcastically before blowing them all up.
- One of Dan Aykroyd's recurring characters on Saturday Night Live is the alien Beldar. He and his mate, Prymaat, tend to intone, "Mebs, mebs, mebs," repeatedly went frustrated or stymied. It's never been detailed in-universe what this expletive means.
- Stargate SG-1: "Jaffa, kree!" or just "Kree!" "Jaffa" is the name of the Goa'uld's servitor race, so that part makes sense, shouting "Jaffa" to get the attention of all Jaffa in the vicinity. But "kree" remained unknown until season three.
O'Neill: Okay, I have to know: just what the hell does "kree" mean?
Daniel: Uhhh... actually it means a lot of things... listen up, pay attention, concentrate.
O'Neill: [incredulously] Yoo-hoo?
- The Strain example listed under Literature carries over into The Strain (TV series), only it's actually said.
- Warhammer 40,000:
- The Space Wolves have "Fenrys Hjolda!", variously translated as "Fenris Holds Out" or "Fenris Endures".
- Averted with the orks, since most of their language is corrupted Gothic (the stand-in for English), so "WAAAAAAAGGGGHHHH!!!!!" is easily recognizable as a longer and louder word for "war".
- The Shroobs from Mario & Luigi: Partners in Time have a single two word phrase in their language that they constantly repeat over the course of the game. It's only at the very end that we finally get a translation: "DESTROY!"
- Mass Effect: The Quarians and "Keelah se'lai" (or just "keelah"). It's explained in one resolution of Mass Effect 3 to mean "By the homeworld I hope to one day see", and is used in many of the same contexts as "oh my god".
- Starcraft series: the Protoss have the Khalani language, and the two phrases which have the most uses are "En Taro Adun/Tassadar/Zeratul/Artanis" and "Adun Toridas". The phrase basically means "In [name's] name," Adun is a historical messiah figure to the dark templar for preventing their genocide by the Conclave. Adun Toridas means something like "Adun hide you", and is a specifically dark templar term referencing how Adun prevented their genocide (En Taro Adun is used by both templar and dark templar, due to having ended up a hero to both groups).
- Warcraft III: The orcs get "Lok-tar ogar!" (Victory or death!).
- In Acquisitions Incorporated, Aeofel's Oath of Vengeance is spoken in a fictional language invented by his player Wil Wheaton on the fly during his first session with the party. In later episodes, it becomes one of his catch-phrases, usually reserved for combat, meaning that it's spoken at least once every session, — but we never actually learn what it means.
- In The Secret Show the Imposters are constantly heard saying the phrase "Ding Badoo!" though it's never revealed what these words mean.
- Voltron: Legendary Defender: The Galra have "vrepit sa". In season 6, Hunk has the opportunity to learn more about Galra culture, but is informed it will be a challenging endeavor from which there is no backing down. With more than a little trepidation, Hunk asks if he'll learn what "vrepit sa" means. When he's told he will, he immediately decides the training will be Worth It.