Stan: You can see your breath hanging in the air, you see homeless people but you just don't care. It's a sea of smiles in which we'd be glad to drown! Kenny: [muffled singing], [more muffled singing]! Stan: That's right!
Daikichi Komusubi from Eyeshield 21 communicates in a language made up of grunts and one-word sentences known as "powerspeak", which can only be understood by strong men like Kurita, Gao, or Mizumachi (and, for some reason, Mamori).
In HeartCatch Pretty Cure!, Snackies communicate entirely in monkey-like "kii!" utterances. Nevertheless, the antagonists can understand exactly what they're saying.
Ash Ketchum has a knack for deciphering his Pikachu's dialog in the Pokémon anime, even though Pikachu can only say his own name.
This seems to be true of most trainers, since they're always around their Pokémon and learn to understand them.
The strange animals on Nagasarete Airantou start this way to Ikuto. Everyone understands their nonsense but him until after he spends an episode trying to look for Kuma-Kuma. Seems that after that they can be heard speaking Japanese. Apparently he 'got used to life on the island'.
Tama-chan the Hot Springs Turtle seems to be understood by Mutsumi in Love Hina, despite only ever saying "myuh".
Arseface from Preacher who due to massive facial trauma cuh uhluh tuh luh thuh (can only talk like this). Most characters can understand him, however.
So can the reader, if they sound it out.
Played with in an issue of Guardians of the Galaxy, where Maximus of the Inhumans can apparently discuss complex scientific concepts with Groot, despite the fact all Groot is saying is "I am Groot!" Of course, since his full name is Maximus the Mad...
Justified by Groot being incredibly intelligent - his lack of verbosity is due to his advanced age - and Maximus being a powerful psychic, as well as crazy.
In the League of Extraordinary Gentlemen, Golliwog verges on this if the reader doesn't apply enough fuzzy logic to him; he's speaking English, sort of, but using incredibly bizarre word choices to do it.
Mazikeen in The Sandman and Lucifer is missing half her face, making her vocalizations barely intelligible to the reader, but the other characters can understand her just fine. In Lucifer her face was eventually turned normal, so that she could experience proper character development without annoying the hell out of readers trying to interpret her speech bubbles.
Doop from X-Force borders on this. As a general rule his speech is rendered in bizarre hieroglyphics and the other characters don't have a literal, word-for-word understanding of what he says. They do, however, tend to get the gist of what he means.
In The Bojeffries Saga, Uncle Festus's dialogue is mostly rendered in pseudo-Cyrillic gibberish-font. The other characters, however, can all understand him.
Film — Animated
Lilo & Stitch: Stitch can persuade someone to let them go, and help Stitch save his ohana with a simple "Ih." Later on it turns out that "ih" just means yes, which makes sense given that it was in response to "you really expect me to [all that stuff] just like that?!"
Aladdin: Aladdin, and sometimes the viewer, can understand Abu the monkey, even though he talks in gibberish. (The most intelligible of Abu's phrases is "Aladdin, wake up!")
Brave has one of the sons of clan leaders who speaks in an unintelligible manner, but his father appears to have no problem understanding him. (As can anyone in the audience familiar with the thicker of the Scottish accents.)
In Wreck-It Ralph, Q*bert only speaks in what's referred to as "Q*Bertese", and Fix-It Felix has to act as an interpreter.
In the Shrek movies, Dragon can only speak in facial expressions and roars. Donkey seems to understand what each roar means, however.
Fish Out of Water in Chicken Little. Double Subverted with the alien kid, who can only be understood by Fish and the alien mother.
Film — Live Action
Hot Fuzz features an elderly cop whose thick rural Gloucestershire mumbling is intelligible to everybody in the Sandford Police Service except Angel (justified since Angel is the only one who wasn't raised in that particular village), and later facilitates a three-way translation of another old man with an even thicker accent who not even Danny can understand. The Gloucestershire accent is so notoriously thick that even the BBC subtitle the worst cases of it. Like most things in this film, the three-way translation (city cop <-> local cop <-> local farmer) is based on a true story that Nick Frost and Simon Pegg collected when preparing for the film.
R2D2 from the Star Wars films communicates entirely in bleeps. 3PO is normally the one to translate (or otherwise reveal) what he is saying for the benefit of the audience, although Luke is shown using a monitor in his X-Wing to translate for him in Empire Strikes Back.
Chewbacca as well, only Han, C3PO, Obi-Wan, and maybe Lando are able to understand him.
The various alien anatomies would make it impossible for everyone to be able to speak one standard language, but understanding other languages is fairly easy - Chewbacca understands english but can't speak it, while Han understands shyriiwook but can't speak it. Anyone wanting to get by as a trader, merc or other interplanetary profession would need to learn at least a half-dozen common languages. Protocol droids like C3PO provide special services as they can both understand and synthetically speak several thousand languages. Also, R2-D2's bleeps are a language of its own, which service droids use and people can learn to understand.
Bubo, the mechanical owl from the 1981 version of Clash of the Titans. What sounded like clicks and whistles to everyone else was perfectly understandable by Perseus. Justified by the fact that it was a gift from the goddess Athena.
Also known as "The Librarian-speak Conundrum" after the Librarian in Discworld, who communicates only with "ook", but seems to able to be understood with perfect clarity by many (but not all) characters.
Only after a period of exposure.
The Librarian also occasionally says "eek", which is usually either an expression of displeasure (or some other negative emotion, such as anger or shock) or a "no", although the exact content of the statement can include a great deal more than that.
Similarly, the Death of Rats communicates entirely by saying Squeak but the few people he interacts with don't have much trouble understanding him, and Quoth the raven is usually around to translate for him.
In The Wee Free Men, Tiffany meets a man who has been trapped in fairyland for years. He can only say "Sneebs!", but when he says it, the sentence he meant turns up in her head.
In the Redwall book The Long Patrol, Corporal Rubbadub speaks only in drum noises, complete with gratuitous Rimshots after jokes made by the other Patrollers. They all seem to understand him perfectly well.
In the many Star Wars novels, there are many characters who can understand R2-D2 or Chewbacca. In a conventional novel, there would be no reason not to include sentences like, "And then Chewie said, in Shyriiwook, 'Pass me the peanuts.'" However, to preserve the ambience from the films, their dialogue is never provided directly like that. Instead, you get something like, "Chewie grunted a request. Han said, 'Sure, pal,' and passed him the peanuts."
Ralrracheen (first introduced in Heir to the Empire is a notable exception, due to his speech impediment that allows non-Wookiees to understand him more easily.
Live Action Television
Buffy the Vampire Slayer: When Buffy meets The Shadow Men, they only speak African (subtitled, of course), but Buffy is somehow able to understand them perfectly.
Lanny in Lizzie McGuire is The Speechless, but Matt (and only Matt) understands him perfectly. One gag involving this is when Dad answers the phone and gets silence; Matt says, "That's for me" and "Hi, Lanny!"
Another gag had Lizze and Matt switch bodies and had Lizzie able to understand him.
Subverted on The Muppet Show, when Beaker says something to Miss Piggy and she snaps, "Beaker, I told you never to talk to me like that!" After he leaves, she turns to the camera and adds, "Because I can't understand it." Similarly, there's a scene where the Swedish Chef is complaining to Kermit, and Kermit keeps going, "I understand." Once the Chef leaves, Kermit gives an Aside Glance and comments, "I don't understand." However, when it's funnier for them to be understandable, Beaker and the Chef sometimes play this straight.
Also played with in the case of the Swedish Chef who is himself The Unintelligible, but has been shown to have a perfect understanding of Beaker and in instance, some other Funny Foreigner Muppets.
When we finally meet the Breen in Star Trek: Deep Space Nine, they speak in an unintelligible electronic buzzing. Despite that, everyone understands them perfectly (as long as their Universal Translator is up-to-date), and even complements them on their eloquence. On a related note, Morn, the silent figure in Quark's bar, has a reputation as a chatterbox.
The Monkey Priest in Father Ted communicates only in 'oohs oohs', but all of the other characters understand him.
In episode 9x05 of Mystery Science Theater 3000, The Deadly Bees, Mike Nelson temporarily dresses as a bee and proceeds to communicate with Tom Servo and Crow in bee language (which involves lots of wiggling around but no actual spoken dialogue). Crow is confused, but Servo understands perfectly.
This trope is older than they think, used as early as Peanuts, with Snoopy being the only character who can understand Woodstock. The adults in the television series are also incomprehensible to the audience, but the characters understand them with full clarity.
Eccles: Just a minute, I'll ask him. What did you say, Little Jim?
Little Jim: (gibberish)
Eccles: Oh... he says he doesn't understand what he's saying, either.
Bluebottle: He's one of Mrs Thatcher's incomprehensives. (a reference to Britain's Comprehensive schoolteachers)
Mario and Luigi in Mario & Luigi: Superstar Saga talk only in pseudo-Italian gibberish, which the English/Japanese-speaking inhabitants of the Beanbean and Mushroom kingdoms understand perfectly...most of the time, anyway.
Honda Tadakatsu in Sengoku Basara, despite only making mechanical noises, seems to have no problems when it comes to communication since other characters are able to hold conversations with him.
Most of the time, these "conversations" consist completely of other characters monologuing. Ieyasu, however, clearly understands what Tadakatsu wants to say to him on some occasions.
In the Fallout: New Vegas expansion Old World Blues, Dr. 8 talks in a string of computer code. With a high enough Science skill, the player character can understand him. The player still can't, though.
This applies to many other robot characters in the Fallout series, such as ED-E, and also the few animals that can be talked to during the series, such as companions Dogmeat and Rex.
Darth Nihilus from Knights of the Old Republic 2 speaks in bizarre language that is possibly generated telepathically. None of the major characters have any trouble understanding it (including the Player Character), but the player is left clueless, as his dialog is not subtitled, in contrast to all the other characters' lines, which are (even when they're speaking perfectly clear English).
It's possible that he's speaking the ancient Sith language, which, since it's not subtitled, may be the Star Wars universe's version of Black Speech.
T3-M4 communicates in beeps and whistles. His dialogue is subtitled, but is not actually translated - it's written out as "Beep-bwoop? [whistle]" and such. The protagonist understands him perfectly, he persuades a pazaak champ to fake-sell him in order to infiltrate a warehouse, and he manages to sass off three assassin droids who can't believe his bravado.
King/Armor King in Tekken only speaks in jaguar growls, but everyone can understand what they're saying just fine. This also extends to Kuma (Bear)/Panda, Roger (Kangaroo), Alex (Velociraptor), Mokujin (A wooden object brought to life), and Ogre (a 'fighting god' who growls and spews a really, really ancient language).
Ma-San in Um Jammer Lammy. Even the player can understand if you turn on the subtitles!
Octodad, being an octopus, speaks only in a series of blubs. He is, however, quite eloquent in his diary entries, and manages to get his points across rather well regardless.
The title character in Wizard's Work goes around with a smallish dragon which never makes any noise other than barking and repeats to the game audience what it's supposedly saying. Whether he can actually understand it or is just pretending is debatable.
Tuba from Baman Piderman speaks only with tuba sounds, but everyone else understands her.
Several cast members of Homestar Runner fall into this, especially The Cheat and Pom Pom.
Homestar: Whoa, Pom Pom! Let's tone down the language before the contest, huh?
In Brain POP, the robots speak in beeps, but humans can understand them.
In Red vs. Blue, the Meta speaks in mainly grunts and snarls, but his partner Wash has no problem understanding him.
The only thing George of A Moment Of Peace ever says is 'Meep,' but his human friend Evi holds extensive conversations with him over tea and while plotting to capture monsters.
Metool D2 from Bob and George is a Shout-Out to R2D2, so his friends have no trouble understanding him. It helps that his friends are superintelligent robots (sort of).
Prospero in PS238 talks in strings of weird alien symbols. This is incomprehensible to all the cast except, for some reason, Angie. Unfortunately, because Angie talks entirely in New York slang, she's also incomprehensible to most of the cast...
El Goonish Shive has Guineas (human / guinea pig hybrid shapeshifter) who in his default form talks via sounds rendered as "Squeek! Squee squee *snort* squee?". His siblings understand this speech though they also can talk with squirrels and hedgecatsnote i.e., cats with hedgehog spines).
Bubbles the Water Cooler in Skin Horse can only say the sentence "Service is my only joy", or sections thereof. Moustachio knows exactly what she's saying, though.
Chris: Dude, you can understand her?
Moustachio: Of course. One only needs to learn five words.
Chris: Robot logic is weird.
In Yu-Gi-Oh! The Abridged Series, "Zombie Boy" (Bonz) says only "brains", and the cast seem to pull deep philisophical musings from the whole thing.
Often subverted and averted when characters just interpret what they want to hear or can't understand him at all (Marik's Evil Council Of Doom).
And often people can't understand him when he talks, as in Evil Council of Doom 4.
That was only Dartz, meaning it was likely just Hypocritical Humor derived from having a character whose accent makes certain statements sound dangerously ambiguous criticize the "pwonownication" of someone that speaks quite clearly.
In Cat Face, Box Cat can only communicate by growling, but Cat Face understands him anyway.
Gorilla from Glove and Boots speaks only in variations on "meh", yet Mario and Fafa seem to understand him just fine. Occasionally, if it makes the joke work better, it seems more like he just speaks in an accent that renders most but not all syllables as "meh", and the audience can thus figure out that he's saying a specific word or short phrase. For instance, in "The History of Television", "Vitameatavegamin" is rendered something like "meh-ta-meata-meh-ta-muh".
In an episode of Futurama, Nibbler zaps Leela with a beam to allow her to understand Nibblonian, which to the audience sounds like gibberish.
Kenny from South Park drifts in and out of this trope; it's a rare character on the show that can't understand him, but that's partly because most of his lines are perfectly normal English just spoken quickly and muffled. Even the audience can pick up what he's saying sometimes... and that explains why he's usually muffled, because his lines would have to be bleeped out otherwise.
In "Obama Wins", Butters becomes temporarily unintelligible when his face swells up from an almond allergy. Kenny ends up being the only one who can understand him, so that he'd slur a sentence, then Kenny would repeat the same thing muffled so Stan and Kyle would know what he said.
Coco in Foster's Home for Imaginary Friends. Whether this is applies to everyone or just people around Foster's isn't consistent: it took a while in the pilot until Mac or Bloo could understand her, but she's been able to do things with strangers (like getting a job) that would require talking.
Bounty Hunter Sixsix of Ben 10 communicates in an alien language that's left untranslated. Vilgax, Kraab and Vulkanis, at least, can understand him perfectly well... And he seems pretty abrasive.
Ikura: No, Wasabi, that's the rodeo. Clowns don't dive in a barrel in golf.
Boomhauer from King of the Hill isn't completely incomprehensible, just hard to understand. However, regular characters have no trouble understanding him, and in fact consider him the wisest and most eloquent character. There are occasionally gags about minor characters not understanding him at all, though.
This seems to only be true in Arlen; in one episode he falls asleep while innertubing and wakes up in Austin, where a policeman thinks Boomhauer's schizophrenic.
In the Looney Tunes short "Rabbit's Kin". it is possible to understand the little rabbit's speech, it's just sped up to the point of near unintelligible, if one were to slow it down you can clearly hear what he's saying.
Done on an episode of Pinky and the Brain in a running gag wherein two old men are sitting in armchairs and one of them will mutter something unintelligible and the other one will understand it and give a reply which leaves the viewer amusingly perplexed as to what the man could have been saying.
H.E.L.P.eR. from The Venture Bros.. The characters who understand him have spent a large amount of time with him.
Lampshaded by Hank and Dermott in the episode Momma's Boys, where they discuss that they are able to understand H.E.L.P.eR, but have no idea how they are doing it.
Octocat from 'Spliced'' can only say meow, but all the other characters can understand her.
Bumblebee of Transformers Prime can't speak normally due to losing his voice processor, rather like his movie counterpart, instead communicating through beeping noises. The other Autobots seem to have no problem understanding him. The only human who gets what he's saying is the Child Prodigy.
And even he is unsure why this is...
The original series had an alien mercenary named Slizardo, whose speech comprised of high-pitched babbling. The Autobots and Decepticons couldn't understand him, but other aliens could.
The Mini-Cons in the Unicron Trilogy initially speak in beeps, (which the humans can somehow understand), although they later learn human language.
The Twins from Men In Black: The Series. Everybody besides J seems to have no trouble understanding them.
Ookla in Thundarr the Barbarian speaks only in unintelligible growls, but Thundarr and Ariel have no problem understanding him.
The Godpigeon from Animaniacs is very mumbly; Bobby typically translates for him.
Sometimes Pesto does so, usually when Bobby is not around. Squit is the only Goodfeather that does not understand what the Godpigeon is saying.
Ivor, from Ivor the Engine, is only able to communicate by blasts from his three-toned whistle. Although he's incomprehensible to most of the human characters, his driver, Jones the Steam, is capable of holding conversation with him. The obvious Alternate Character Interpretation, that Jones the Steam is harmlessly insane and "Ivor" a mere Companion Cube, might well have been intentional.
In "The Dragon", however, Ivor won't make any noises when the lady from the antiquarian society is there, implying to her that the dragon was also imaginary, but to the viewer that he does really talk the rest of the time.
Meap from "The Chronicles of MEAP" episode of Phineas and Ferb speaks only the word "meap". Once he tears the Intergalactic Translator Mustache off of his foe Mitch and dons it, Meap is quite articulate.
Poof from The Fairly OddParents varies between only being able to say "poof" and being able to speak but incapable of formulating a sentence, yet everyone understands him. Lampshaded in one episode where Foop says he can't believe Poof got a part in the play, as he's "a much better actor, who can actually speak real words!"
Spoofed in My Little Pony: Friendship Is Magic, where Pinkie Pie acts like she understands her alligator Gummy, despite his having no real means of communication. It quickly becomes clear that she's just guessing.