Mouthy Kid

In the '50s the Mouthy Kid would have been slapped upside the head and shipped off to the Military School. Children were little angels, or at least tried to be (Leave It to Beaver, My Three Sons, Family Affair). That all changed when Arnold on Diff'rent Strokes popularised the bratty kid. Television parents have been dealing with sass ever since.

Likely started out as a subversion of the Children Are Innocent attitude that had prevailed since Victorian times.

See also: Bratty Half-Pint and Plucky Girl. Contrast Constantly Curious, who talks as much but isn't as bratty.

Anime and Manga
""There's no choice. Big sis isn't very bright, so she has to make a living with her body!""
 * Shin Chan: Shinnosuke "Shin-chan" Nohara, although he is a five year old whose dialogue is pretty much "farty poop fartfart", he crosses the realism line once he calls his mom flat-chested (in both the original and the Gag Dub).
 * Science Ninja Team Gatchaman: Jinpei "The Swallow".
 * Fullmetal Alchemist: Edward Elric gets called out for it at one point. "An Edward who can't use alchemy is just another kid with a foul mouth."
 * Mazinger Z: Shiro Kabuto. He is a Deadpan Snarker has no trouble telling exactly what he thinks. His older brother, Kouji Kabuto finds them annoying sometimes because Shiro often thinks his actions or plans are dumb. He also appeared in Great Mazinger.
 * UFO Robo Grendizer: Goro Makiba, Action Girl and Love Interest Hikaru Makiba's Annoying Younger Sibling. He is nosy and loud-mouthed, and loves teasing or taunting his sister.
 * Getter Robo: Genki Saotome is another example of child often tells what he thinks; a trait is not appreciated for the adults and teenagers he meets.
 * Bleach: Amazingly, Kuchiki Byakuya was this as a teenager.
 * Baccano!:
 * Thanks to being Older Than He Looks even before Immortality, as well as an all-around smartass, Firo Prochainezo gives off this impression to nearly everyone he meets even between the ages of nineteen and ninety.
 * The odd case of Czeslaw Meyer, who has been ten years old for a couple hundred years. While he had a pretty rough time of things, someone decided to Throw the Dog a Bone and give him a normal life. He spends the next seventy years in the novels invoking this trope, particularly while Walking the Earth.
 * Super Milk-chan: The title character is this. In the Adult Swim dub she regularly calls her friends dumbasses.
 * Yuuki from Baby Steps, the youngest member of Love Interest Natsu's tennis club who originally thought the protagonist Eiichirou was either a spy for another club or a "degenerate old stalker". Since then, he never misses an opportunity to give E-chan a hard time.
 * Ayanes High Kick has Ayane's annoying younger brother Kenta, who we first see butting into an argument between Ayane and her mother about Ayane skipping school to attend a pro-wrestling tryout.


 * Bikky in FAKE is a particularly mouthy Bratty Half-Pint. Especially when he's mouthing off at Chivalrous Pervert Dee whom he sees as nothing more than a Handsome Lech chasing after his adoptive father Ryo.

Comic Books

 * Calvin of Calvin and Hobbes

Film
"Danny: Pick us up in two hours. Ronnie: Fuck you, Miss Daisy."
 * Mouth in The Goonies is appropriately nicknamed. "Shut up, Mouth!"
 * Ip Man 2 has.
 * Ronnie, a middle schooler of hilarious retorts and apparently vast cinematographic knowledge, in Role Models


 * Watch The Birdie an early Bob Hope film, has a mouthy little girl.
 * The Philadelphia Story/High Society has Dinah.

Literature

 * IT by Stephen King: Richie Tozier.
 * In Time Enough for Love, protagonist Lazarus Long travels back in time to meet his family in 1917 Kansas City, Missouri. There he encounters his past self, Woody, who is already an up-and-comer, about as shrewd, stubborn, and mouthy as it's possible for a five-year old to be, and kept in line only with generous application of paddle to arse. His (and Lazarus') grandfather Ira remarks -- in unknowing irony -- that the kid is going somewhere, if he somehow makes it to adulthood without being murdered by his parents. He has no idea.
 * Matteo Ta'anari in Someone Elses War. But only to kids his own age--never to adults or small children. And he doesn't get shipped off to military school so much as shipped off to the military.

Live Action TV
""I want fish and chips! This tastes like bollocky wankshite!" "Gordon MacPherson says you call them dykes, because you have to stick your finger in them." "I want to fuck Naomi [beat] I do, get over it.""
 * Modern Family: Alex, the middle child. She does little else on the show than make snarky comments.
 * Leave It to Beaver: Exception that defines the rule: Eddie Haskell -- bratty around his peers, but with a nice phony front of shallow flattery while he was around adults.
 * Malcolm in the Middle: All of the boys. Francis is sent off. His advice helps keep Malcolm from the same fate.
 * The Partridge Family: Danny Bonaduce's character is bratty around his peers but puts on a nice front around adults.
 * Darlene Connor of Roseanne epitomizes this trope in the early seasons until she grows into quite the Deadpan Snarker as the show focuses more on her. DJ also sometimes fell into this trope as well.
 * Skins : James Fitch (Katie and Emily's kid brother), most likely due to the influence of his (unseen) friend Gordon MacPherson.


 * Welcome Back, Kotter : While the Sweathogs are considerably older than the usual Mouthy Kid, they form an obvious precedent.
 * Bad Boy: Moon Won In in this Korean Drama: she sneaks beers from her sister, tries to buy cigarettes even though she's underage, and in one episode steals money from an apparently unconscious man.
 * Misfits: Nathan Young
 * Good Luck Charlie: Gabe Duncan IS This Trope

Radio

 * Possibly the Ur Example, Fanny Brice's Baby Snooks was somewhere in between this and Constantly Curious. Her sole reason for existence appeared to be to drive her father to the very brink of insanity, but she did it without apparent malice -- just pure innocent mischief. And given that the character was created in 1912, and continued to be wildly popular until Brice's death in 1951, it shows that Arnold from Diff'rent Strokes far from created the trope -- he just incarnated it for a new, more relaxed generation.

Theater

 * Moth from Shakespeare's Love's Labour's Lost.

Video Games

 * In Fallout 3 there's a town called Little Lamplight, which banishes its residents when they turn 16. Because of this, the town is filled with kids who walk around swearing because there's no one to tell them no. In fact, the mayor's greeting to you is basically "who the fuck are you?".

Western Animation

 * Beavis and Butthead: Mike Judge said that dialogue is a better reflection of the real-life Mouthy Kid -- not too clever, relies heavily on toilet humor -- because in reality, kids aren't as smart as a roomful of Harvard-graduate writers.
 * Toph Bei Fong from Avatar: The Last Airbender practically defines this trope. She is not afraid to speak her mind or tell someone off, no matter their position or title in life.
 * Artie Smarty in Kim Possible.
 * The Simpsons : A popular example: Bart Simpson. And Lisa Simpson.
 * Star Wars: The Clone Wars: has Ahsoka Tano in a very odd example, seeing as Jedi Padawans are encouraged to be respecteful.
 * Darkwing Duck has the title character's adopted daughter, Gosalyn, who is quite a handful (while also often helping to save the day).
 * Ben 10.
 * Marcia the marsupial mouse from Blinky Bill.
 * Scooby Doo: Scrappy Doo.