The Unintelligible in Literature.
- Discworld:
- The Librarian says only "ook" and "eek" but can be understood by some characters. There's a Lampshade Hanging in Moving Pictures, where the Bursar tries to explain to the Archchancellor the difference between the "ook" for "yes" and the "ook" for "no," and it becomes apparent he doesn't really know how he understands what the Librarian says.
- The Death of Rats only says SQUEAK, but has no problem getting his opinions across (or if he does, Quoth the Raven can translate).
- The Discworld Almanack quotes Friar Boy Odious, Master of the Scumble, as saying "Fw'yo huzzy bwoy willups hut? H'shush say wint!" (Scumble being a Gargle Blaster of a hard cider, traditionally made with bizarre alchemical additives, in presses made of lead.)
- Sunny from A Series of Unfortunate Events talks only in babyspeak, which is translated either by her siblings, or by Lemony Snicket's distinctive and verbose definitions. As the series goes on she gradually becomes more intelligible, going from gibberish to slurred words to distinct words to her first full sentence: "I am not a baby."
- Razorback of the Whateley Universe can only make weird growling and barking noises. Since he looks mostly like a velociraptor, it's not really surprising he doesn't have a human larynx.
- The Blind Side has Ole Miss' head coach Ed Orgeron, aka Coach O, whose thick Cajun drawl borders on gibberish to everyone except fellow Louisianan (though not Cajun) Sean Tuohy.
- Baby Kayla from The Giggler Treatment can only say 'a-bah' but everyone understands her anyway, because they love her so much. To the point where Mr. Mack actually mistook 'a-bah' for Kayla's first words... "Mind the poo!" (which were, incidentally, said by Rover the dog. It makes sense in context.)
- Hodor from A Song of Ice and Fire says exactly one word: Hodor. In fact, it's not even his name (his real name is Walder). Though Bran occasionally notes that he doesn't know what Hodor's trying to say, it's generally pretty obvious from the context.
- David Weber has fun with this — neither the Orions in the Starfire books nor the Rish in In Fury Born have the necessary vocal apparatus to speak English. On the other hand, both races can understand English perfectly well, and vice versa, even if it can be a bit hard on the human ears. There is one Noodle Character who can speak High Rishathan, but the same person could also "reproduce exactly the sound of a buzzsaw hitting a nail at 8000 RPM"...
- Tinker Gnomes in the Dragonlance universe speak extremely fast and have to be reminded constantly to slow down so other races can understand them.
- Subverted with Toth from The Malloreon series. Written in the prophecies as "The Silent Man", he is Exactly What It Says on the Tin. He only communicates with vague hand and arm gestures, yet anyone paying attention to him seems to understand him clearly. It takes until the last book, "The Seeress of Kell," for Durnik to finally catch on to what's really happening: his gestures conceal the fact he's actually a telepath.
- In Dave Barry Slept Here, Senator Sam Ervin speaks a Deep Southern language "similar to English, only unintelligible."
- From Peter Pan and most adaptations, one particularly iconic example of this trope is Tinker Bell's fairy language, which sounds like...well...a tinkling bell.
- Gornab's speech in Rumo & His Miraculous Adventures is so messed up, only his chancellor can understated him. OTOH, he consistently manages to speak all words exactly backwards (by syllable, not by sound or letter).
- Wuthering Heights has a meta-example in the form of Joseph. It seems the author tried a little too hard to communicate his accent. It leaves you wondering if what is typed is language at all. Luckily there's an entire website dedicated to helping readers understand what he says, one of which can be found here.
Joseph:Yon lad gets war und war!' observed he on re-entering. 'He's left th' gate at t' full swing, and Miss's pony has trodden dahn two rigs o' corn, and plottered through, raight o'er into t' meadow! Hahsomdiver, t' maister 'ull play t' devil to-morn, and he'll do weel. He's patience itsseln wi' sich careless, offald craters—patience itsseln he is! Bud he'll not be soa allus—yah's see, all on ye! Yah mun'n't drive him out of his heead for nowt!' - The Divine Comedy:
- In the fourth circle of Hell (where those who hoarded and wasted their wealth are punished), Dante and Virgil meet Plutus, the Roman god of wealth, who is heard muttering random gibberish to himself.
- Like in the Book of Genesis, those who built the Tower of Babel are punished for their prideful attempt to surpass God by having new languages randomly imposed on them. The only one to keep the first tongue is Nimrod, the only person still able to understand it, leaving him to babble, unable to relate with others due to betraying his most essential relationship, that one with God. His fate foreshadows the madness and isolation of the leader of Hell, Lucifer.
- The Devil, despite having three mouths, has lost all reason to communicate with others. Now, his mouths are only used to rip his fellow damned apart like meat grinders, corrupting his ability to love and connect with others as a tool to destroy and shred.
- The Baroque Cycle: The Scottish Lord Gy speaks with such a thick Scottish Funetik Aksent that he's unintelligible to Englishmen. An extremely polite and effete English lord eventually has to confront him on the fact that he is not speaking English.
- Jonas from Saving Max speaks gibberish that only his mother understands. This makes it much easier for her to abuse him without getting caught.
- Spook from Mistborn: The Original Trilogy. It's not that he can't speak, it's just that his speech patterns are absolutely steeped in a specific dialect of street slang that almost nobody else uses anymore, and he leans into it so much that it renders him nigh-incomprehensible to all but a few. Just to give you an sense of what its like, when trying to say 'I was running to that place', Spook says it as 'Wasing the run of there'. Hilariously subverted in the Sequel Series, set over 300 years later, where Spook's bizarre slang is now regarded as a real language called High Imperial by clueless historians, effectively becoming the setting's equivalent of Latin.
- Lorna of The Curse of M is a Downplayed example. Her Dublin accent is so thick that when she goes to America, she's asked more than once if she speaks English. Only two characters have no trouble understanding her, and one of them can read her mind.
- Lost Voices: Before Luce turns into a mermaid, her only friend is a mentally disabled ten-year-old boy named Gum, who speaks mostly in moans and gibberish.
- In Craig Shaw Gardner's Bride of the Slime Monster Roger visits a beach-party musical world where the antagonists are the Mad Mumbler and his Motorcycle Mob. As befits his nickname, the Mad Mumbler speaks so unintelligibly that even his second-in-command/interpreter Sneer has trouble understanding him at one point.
- Twig: Dog has been so heavily modified that his jaw no longer functions really well and as a result, he can't speak English. He communicates in a grunting, growling fashion. However, he's far from stupid, and his longtime partner Catcher is able to understand what he's saying, and usually acts as an interpreter. Gordon also took the time to figure out Dog's speech, which goes a long way toward endearing him to Dog.
