Used in the E-Trade commercials featuring a baby that apparently knows more about investing money than most adults. This is Played for Laughs and not intended to be taken seriously.
"Just a man and his thoughts. [Beat] And his iPhone. With an E-Trade app."
A Dutch advert for a supermarket chain has science tidbits trading cards or something similar. A cop pulls over these two guys in a car saying "Well you nearly went the speed of light, didn't you?" in comes a kid in the backseat explaining exactly how fast the speed of light is compared to the vehicle. The officer, flabbergasted, says "I'll let you off this one time." kid replies "I'll do the same, then."
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Kyon. The offhand math references, the science, the multi-cultural references, ancient philosophy, history, phonetics. All from a supposedly average High School Student. Top that with how his choice of words and terminology even in casual dialogue, in Japanese, makes him sound like someone in their 50's. Then again he is telling the story in the past tense... That, and Kyon is heavily hinted to be much, much smarter than he lets on, occasionally. After all, he did solve the Remote Island Incident with little help.
Features heavily in PS238, mostly from children who are Wise Beyond Their Years such as Zodon, Victor and Tom (Murphy may or may not count. As a child, that is). USA Patriot and American Eagle also do this a lot, though much of what they're saying sounds more like rehearsed talking points than things they've come up with on their own. Most of the kids avert it, however.
In The Man With Two Brains, when Steve Martin, playing a brain surgeon, hits a woman with his car he turns to the little girl standing nearby and tells her to phone his hospital, giving her explicit medical instructions. She repeats everything back word for word and the dialogue continues as follows:
Girl: Sounds like a subdural hematoma to me. Dr. Hfuhruhurr: Oh, it does, does it? Well, it's not your job to diagnose. Girl: But I thought... Dr. Hfuhruhurr: You thought, you thought. Just go. Three years of nursery school and you think you know it all. Well, you're still wet behind the ears. It's not a subdural hematoma. It's epidural. Ha.
This was featured heavily in The Wizard, where all the kids talk like drug dealers and the adults talk like, well, kids.
The little girl at the end of Spider-Man 3 haggled like a professional adult and managed to con a fully grown man.
North and Winchell from North. But then again, the entire point of North is that the bulk of the movie is a hallucination being experienced by a bigoted so-called child prodigy with an overinflated sense of his own importance, so maybe that's not so surprising.
In Annie Hall Alvy Singer remembers his child self getting in trouble for kissing one of his classmates. When he defends himself as just exhibiting natural curiosity, the little girl says, "For God's sake, Alvy, even Freud spoke of a latency period."
All of the kids in Enderís Game are ostensibly precocious child prodigy geniuses, making this less unlikely than it would seem.
Another Pre-Teen Genius, Artemis Fowl, uses this extensively as well. The Eternity Code sees him scare the wits out of an ordinary waitress with his adult (and ultra-sophisticated) behavior, and in The Time Paradox it gets put into perspective when we realize that the "present" Artemis is actually a lot better at acting his age than he was when he was 10. It is tempting to blame Parental Abandonment for this, but The Time Paradoxalso revealed that he was acting — and speaking — like that even before his father went missing.Though he still thinks like a kid in some ways; in the first book, Holly says something sarcastic about lollipops as she's making her escape, and Artemis' first two thoughts are, in order, that he doesn't like lollipops, and that using the word "lollipop" is beneath the dignity of his intellect. Which, of course, leads one to the question of how he plans to patronize children himself when he grows up.
Kendra and Seth from the Fablehaven books often use large vocabularies and explain concepts that a thirteen and fifteen-year-old wouldn't be able to fathom. Of course, seeing all of the other words thrown into the narration of the story, the author may just be trying to get kids to learn how to use a dictionary.
The Achings only own so many books, and one of them is a dictionary. Also humorously subverted in that Tiffany doesn't know how to pronounce some of the longer or more unusual words. Which is typical of children who learn words from reading books instead of from hearing them.
Played for laughs in A Spy in the Neighborhood with smart preteen Paul, who goes into too much detail about mundane things in an almost stereotypically Asperger's-like fashion.
This was taken to ridiculous extremes in William D. Hayes' Project: Genius. Basically, the main character discovered while doing homework that reading the dictionary to his infant brother would put him to sleep (especially the "S" section). This took place shortly before he decided that his school project would be convincing a local TV station to broadcast a show about his brother as the "typical baby." Shortly before airtime, he pointed at his brother and told him to say "Da," and the then eleven-month-old kid said "Pusillanimous."
Played with in Judy Blume's Fudge series - after spending the entire book misusing or mispronouncing words and expressions he picks up from his brother and parents, he finally figures out how to use them correctly just in time to say them to a visiting author/artist at his school, making him seem very precocious.
Inverted, ironically, in Wesley Crusher; though he's supposed to be a little professor, he sometimes talks like someone half his age. The first season episode "The Naked Now" has him saying "It was an adult who did it!", for example.
Dawson's Creek was forged out of this in the fires of Mt. Doom. It was clever at first...then just annoying.
This was actually lampshaded in a commercial for reruns on TBS. It went something like, "They act like kids, but they don't talk like kids. Coming up next...Dawson's Creek!"
Both Frasier and Niles Crane on Frasier, in flashbacks to when they were kids. Also evident in excerpts of their childhood writing, like journals, essays, etc.
Henry Dillon from Shake It Up. He's a 8 year old super genius.
Peanuts arguably pioneered this trope, between Charlie Brown's expositions on his anxieties, Linus quoting various authors & philosophers, and of course Lucy and her "Psychiatric Help" booth.
Calvin and Hobbes featured allegedly six-year-old Calvin, who didn't talk like any six-, or even twelve-, year-old that most of us have ever met. Bill Watterson sometimes lampshaded this by having Calvin follow up a spate of Little Professor Dialog with a more typical six-year-old reaction.
The whole joke of about one third of the strips is Calvin expressing a stupid idea natural to a six-year-old with the language of an adult. For example, when he justifies spending an afternoon collecting frogs by saying: "I must obey the inscrutable exhortations of my soul."
In Non Sequitur, Danae embodies this trope to a tee, but with an alarmingly good justification. She largely bases her assumptions on what is acceptable social behavior by watching politicians and pundits on television. When she emulates them, she'll use the words pretty much the same way they do — to make a bizarre political point. In spite of the fact that she only uses very basic mimicry to develop her points, she is still able to gain think-tank funding and cable news time because her arguments end up indistinguishable from legitimate pundits — even though her thesis is usually something ridiculous like "boys are boogerbrains".
In fact, pretty much any newspaper comic where a kid character is supposed to represent some element of the adult world is an example of this:
The Argentinian comic strip Mafalda was published and set during the Cold War and revolved around the titular character, a little girl (5 years old at the start of the comic, though she aged in real time) who was deeply concerned about humanity and world peace, and would comment at length about the geo-political situation at the time. Her friends, while not concerned about politics, would also frequently talk like adults. However, Mafalda was the most extreme case and often lampshaded at times, such as her parents occasionally telling her to worry about things "her own age" and her friends occasionally tiring of her musing.
A Dilbert comic portrayed the title character as a child trying to get permission to skateboard near a construction site. When his mom brought up the "Jump Off a Bridge" Rebuttal, he replied "Well, that would depend on many factors, including height, training, and equipment. But if 100% of the people who jumped off cliffs said they enjoyed it, as in my skateboard example, then I would conclude that it was safe. A better question might have been, 'If everyone wore clothes, would you do that?'" Rule of Funny, of course.
Frazz regularly employs 5-9 year old students more intelligent than most adults. The other main character aside from Frazz himself, the irresistable Caulfield, plays a bored genius who has read more books in a month than most adults do a year and spouts observations about life and culture like nobody's business. Every other student Frazz gets to know likewise seem to carry inexplicable wisdom that, if only put into the hands of their administrators, would probably fix many of America's public education problems.
Ernesto in Cul De Sac looks like a pint-size Latino John Hodgman, and it carries over into the way he talks.
Alice and the other preschool children aren't always this advanced, but their vocabularies and speech patterns are pretty elaborate for their age. They can play this trope totally straight as well, such as when Alice describes one of her paintings as "post-expressionistic imagery of power, innocence, and repression."
The Chick Tracts occasionally slip into this with his, with small children (surely no more than eight years old) knowing waaaaay too much about the Bible. And actively preaching. It is true that kids from religious homes will probably have some Biblical knowledge, but they're much more likely to say something along the lines of "Jesus is my friend!" in everyday conversation than "The substitutional atonement doctrine explains why the incarnation of Christ was necessary for mankind's redemption."
Pearl of Ace Attorney is surprisingly deductive, logical, and aware of the consequences of many things legal and moral, often seen giving advice and added perspective to Phoenix Wright when in a serious moment. Sure, she is the coddled daughter of a Chessmaster, and a spiritual prodigy, but the girl is only nine. Then again, her favorite TV show is Kid's Masterpiece Theatre. In Japanese, she also has an impressive grasp on the complicated system of honorific/humble language. The last case in the Phoenix trilogy, however, has as a plot point that while she talks above her grade level, she's not too hot at reading yet. (In the Japanese version, she can't fully understand kanji; in the English version, she was a poor reader as well, but the phrases in question were in English: Gravely roast -> roast's gravy.)
Played with in Golden Sun: The Lost Age by Eoleo, who thinks like this when you use your Mind Read spell on him... because he's not old enough to speak yet. However, it also gets lampshaded; one of his playmates complains about his "grown-up attitude".
In Penny Arcade, Tycho's niece, Anna or "Annarchy," not only speaks with almost ludicrous Sesquipedalian Loquaciousness, apparently taking after her uncle in that regard, but is advanced enough as to be the standby Professor type in the computer game. There is one strip where she speaks somewhat normally, and is immediately chided for it by her uncle.
Also, she beat the original Famicom versions of Final Fantasy 1-3. In Japanese.
Several Homestuck characters speak like this. Rose is probably the worst offender, being a thirteen-year-old human girl who talks like H.P. Lovecraft. Karkat and Kanaya talk in a garbled (and in Karkat's case, sweary) version of this kind of speech.
Whateley Academy is supposed to be a high school for mutants, with most of its students indeed belonging to the right age group because mutations generally manifest during puberty. You wouldn't believe it from listening in to most of their conversations, though. (In some cases it's justified — some of these kids were already highly educated before they arrived and/or have superhuman mental faculties —, but it's too universal a phenomenon to be explained by that alone.)
Penny from Inspector Gadget used semi-big words like "infiltrate" and such, but that's not too bad. What did stick out, however, was something she said in an episode where MAD was trying to turn metal into gold: "If MAD can turn metal into gold, they'll undermine the world economy!" Wow! For someone who's not even in middle school, she's able to understand a concept that most don't learn — or even understand — until high school! Then again, her uncle is a cyborg and she runs around with a laptop before laptops even existed, and no explanation of why is ever given. Penny might just be really, really smart.
Hey Arnold! had a kid who said that he wanted a role model "that I can look up to emulate." Seeking a role model, and using a word like "emulate"? Not nearly as bad as Arnold telling a marketing man that he "saturated the market" with too much of his product. How old are these kids? Fourth grade.
Twilight Sparkle: (grunts in frustration) That something really bad is about to happen!
Try watching any cartoon that has been dubbed to Latin American Spanish and pay attention to the dialogue. When a little kid starts talking fancy, with neutral accent and using baroque words, the rest of the world assumes he/she saw way too much TV. And there starts the mocking.
The kids in Recess with Gretchen being the biggest example.
Jimmy Neutron. Admittedly he tones it down a lot of the time, but sometimes he just can't help it.
Dexter from Dexter's Laboratory is a young mad scientist who uses big words a lot in his talking.
In a DVD extra from the second Harry Potter film, 12-year-old Daniel Radcliffe tells us in an apparently unscripted talking head bit that "Basically, in the first film Harry is very reactive to everything around him, and in the second film he's very proactive."