When Ranma One Half's Shampoo speaks Chinese to Mousse, she's eloquent to the point of being archaic, but her Japanese is pretty bad (it's translated as Hulk Speak in English).
Shenhua from Black Lagoon is Taiwanese and presumably speaks fluent Chinese, but her English (and Japanese, in the original) is utterly dreadful both in grammar and pronunciation, to the point where Revy (who is Chinese-American) nicknames her "Chinglish." It's not a good idea to take her poor language skills for stupidity, unless you want to beknifed to death.
Kuu Fei from Mahou Sensei Negima!, despite her grades is not stupid; her physical/kinetic ability sits at a genius level. She also occasionally speaks in her native Chinese, at which she comes off as perfectly concise. However, she speaks Japanese in a stereotypical "Chinese person speaking Japanese badly" manner, which is translated similarly to Shampoo's speech in the above example.
Simon from Durarara!! who seems to only speak broken sushi sales pitches in Japanese yet has rather insightful conversations in Russian. Subverted with the Russian Mafiya member Vorona; she speaks Japanese fluently, but her tone and syntax come off as being robotic and stilted. It's mentioned that she talks better in Russian, but how much better is an everyone's guess — she's a pretty strange girl in general.
A written version in Neon Genesis Evangelion, Asuka fails her math exams at school. However, when Shinji is having trouble with a problem, she solves it in her head. When Shinji expresses his amazement at how she could possibly be failing math, she explains that she hasn't learned the kanji yet and just can't read the exam questions. Made more apparent by the fact that she apparently has college-level degrees and is basically a child prodigy as well as an Evangelion pilot. It's likely that kanji is really the only reason she's in school at all.
Subverted in The World God Only Knows, since Elsie, after failing her first test, claims it was because she couldn't read anything except the language of hell. Later on, even after being taught by her Teen Genius comrade Keima, she is still not very good. But that was predictable.
Inverted with Cyndi Manabe of Best Student Council. Throughout the series she speaks halting, two-or-three word Engrish sentences, with the penultimate episode revealing she actually has fluent Japanese, but her mother, who isn't eloquent, convinced her it was incorrect.
Minami in Baka and Test: Summon the Beasts is in the lowest-level class in their school, despite being of probably above-normal intelligence (she's already fluent in two languages at the age of 15). She gets very good grades in math, however, as long as there are no word problems, because, having lived in Germany most of her life, she only reads Japanese at an elementary-school level.
Natalya in Y: The Last Man. Her attempts to speak English result in statements like the following:
"Stay frozen! One small step, and I am executing both your faces!"
("What the hell is going on?") "No, hell is not going - it is coming right for us!"
"Because of Israeli womens, I now have many of banging artillery to use on anyone who might brought trouble in."
"Be screwing yourself! I am not letting the only son of Russia grow up to be a homosexualist!"
"Unhand child or I unhead you!" (Although that one does work pretty well as a Pre-Mortem One-Liner.)
Reversed by the Starman villain Simon Culp. He made a point to learn a very upper-class register of French as overcompensation for the perceived contemptibility of his native Cockney English.
Octoboss thinks he's one of these. "English am SECOND LANGUAGE, fool!" He is also covered with realistic, sucker-lined tentacles. He would be much more hilarious if he didn't, you know, beat the crap out of people. Kursk, as well.
Kitty Pryde's "pet" dragon Lockheed doesn't make statements much more complex than "hmph" and the affirmative "yeh", but it's repeatedly mentioned through many X-Men series that he is much more intelligent than any of the humans around, merely physically incapable of pronouncing human words. In fact, he's one of the smartest and most thoughtful members of the Pet Avengers.
Groot, badass tree (yes, tree) of the Guardians of the Galaxy, never says anything but "I AM GROOT!" But his inflection and tone matter greatly… He used to be able to talk normally.
Played with in an issue of Luba In America where Venus and Yoshio are at a restaurant and Venus' aunt Fritzi shows up and strikes up a conversation with Venus in Spanish. Yoshio, who doesn't speak Spanish, thinks it sounds beautiful and imagines the two as elegant superhuman beings, but in reality, their conversation is mundane.
Xavin of the Runaways often came off like an arrogant, overly masculine jerkass. When called on it, she has insisted that her words would have sounded much less arrogant in her native language.
Mala in Wonder Woman speaks English but has a tough time with idioms. When she comes to the U.S. to find the princess, she spends some time in a women's prison. She helps her cellmates escape, and they tell a colleague "She sprang us from the jug and now we're on the lam." Confused, she responds "I neither sprang from jugs nor sat on lambs."
Once you realize that Nell Kellty uses Biblical words and phrases in a heavy North Carolina accent, mingled with her mom's dysphasic traits and a secret language from her childhood, she becomes almost completely comprehensible.
Star Wars. Master Yoda. Great Jedi master he is. Lift a starfighter with his mind he can. Speak Galactic Basic well he does not. Apparently, the syntax he uses is 900 years old, so it ends up like this. Given that his first appearance in the film involved messing with Luke's head with a bit of Obfuscating Stupidity, it's quite possible that he's perfectly capable of speaking modern Basic but simply chooses not to, and at least one Expanded Universe novel ran with this interpretation.
Bela Lugosi found English very difficult and learned most of his lines in films phonetically, resulting in his infamous mis-emphasized deliveries. However, The Black Cat is worth watching entirely for a scene where he gets to speak a bit of his native Hungarian, and sounds perfectly natural.
Shogun goes both ways with this trope, with some Japanese speaking English poorly, and Blackthorne struggling and even getting in trouble trying to speak Japanese.
Rudyard Kipling sometimes does this. In the prototype Mowgli story, "In the Rukh", when the German Muller is speaking English, his accent is rendered atrociously, but when he's speaking to Mowgli (presumably in Hindi) it's translated in the same "Shakespearean" Englishnote It appears more antiquated than it is to modern readers as Kipling uses "thou" and "thee" to render the familiar second-person singular pronoun of those languages; in modern English, "thou" has fallen into disuse except in a few dialects and religious texts. Kipling uses to render most non-English languages. This applies even more obviously to several characters in Kim, especially to Hurree Babu and Kim himself, at least until he becomes the recipient of an English education at St. Xavier's.
The little girl Aily from "Five Get Into a Fix" by Enid Blyton speaks beautiful Welsh, but her English is very broken ("Aily hide", "Aily not tell", etc.)
In Pinocchio's Sister, this is lampshaded by an immigrant boy named Stashu, who says that he sounds stupid in English.
The African shaman character N'longa in Robert E. Howard's Solomon Kane stories comes off as a racist stereotype with his silly pidgin English and silly attitude, but in the rare occasions he addresses Cane with his native language, his speech becomes formal and sophisticated, clearly indicating that he's deliberately using Obfuscating Stupidity to keep the Puritan Kane from freaking out too much by his black magic.
Used as a Take That by C. S. Lewis in Out of the Silent Planet. Mad Scientist Weston makes an eloquent, if blatantly ethnocentric, speech in English, but Ransom struggles to translate it adequately into Old Solar (some of the concepts don't even exist). It strips away much of the rationalizing. When Weston gets frustrated and tries to express himself directly, it gets even worse.
To an extent, Marco in An Instance of the Fingerpost, who is eloquent in Italian and Latin, but clearly has some difficulties with English, that lead to misunderstandings because of the language gap. It does seem unlikely though that he's the gibbering Funny Foreigner in English that one of the other narrators presents him as, since none of the other narrators have this impression.
In the Myth Adventures books the dragon Gleep can only say one word, "Gleep!" Turns out that he is highly intelligent, but you would only know that if you spoke dragon.
Firekeeper in the Firekeeper Saga by Jane Lindskold. She speaks poorly in three human languages, mostly because she drops anything she deems "unnecessary," like the finer points of grammar, but is fluent in the language of the Wise Beasts, her native tongue. Though she does make an effort to speak clearly on formal occasions or when she needs to express a precise idea.
Warrior Cats has Midnight the badger, who has terrible grammar whenever trying to speak cat with any of the feline protagonists (she can also speak rabbit, fox, and, of course, badger). Despite sounding like she was dropped on her head, Midnight is just as insightful and intelligent and as any medicine cat, and has been very helpful to the Clans.
Professor Timofey Pavlovich Pnin, in Pnin by Vladimir Nabokov, is a Russian hired to work at a New England College. His weak English skills make it hard for some to appreciate his brilliance.
Dave Sedaris's Me Talk Pretty One Day, which causes his French teacher extreme grief. He finally understands French... but can't speak it properly himself.
Professor Van Helsing (a Dutchman) in the original Dracula is an interesting quasi-example of this. He speaks the English in syntax quite broke, but he's really quite eloquent even then, in that he has a great vocabulary.
The Reynard Cycle: Hirsent's poor mastery of the Southern language is portrayed this way. She lapses back into Calvarian several times in order to speak more eloquently.
Sherlock Holmes story "A Scandal in Bohemia" features a letter written with English words and German syntax, which is one of the clues Holmes uses to narrow down the origin of the letter.
Played straight in The Pickup by Nadine Gordimer. A white woman (South Africa, post-apartheid) meets an Arab man at a garage after her car breaks down, and invites him to lunch with her friends. He speaks decent English, but sometimes has difficulty with vocabulary (Gordimer portrays this in a sympathetic manner). Later, it turns out that he's an illegal immigrant, so he gets deported and she follows him back to his (unnamed) country... wherein the situation is reversed. Suddenly he's the eloquent one and she's the tongue-tied foreigner.
Lampshaded in The Hallowed Hunt by Lois McMaster Bujold, Jokol the Skullsplitter speaks the local language brokenly, he's capable of composing epic poetry in an evening in his own language, and has memorized stories in the hundreds, if not thousands. He's called Skullsplitter because he can tell so many stories his men fell like their skulls will split.
Harry Dresden is aware of this trope, as well as how horrible his Latin is. So when Proven Guilty comes around and he has to make an eloquent defense of Molly Carpenter to keep her from being executed for black magic, he manipulates the situation so that he can present his defense in English.
Possibly applies to the Librarian from Discworld. He's a former human turned into an orangutan after a magical accident. Although very intelligent, all he can say is "Ook". However, he says it with such inflection and expressiveness that those who know him well can understand the (sometimes quite complex) things he says perfectly. As they put it, "We've just got into the habit of understanding him". He's also started work on an Orangutan/Human dictionary. So far he has gotten as far as "Ook".
Ousanas from the Belisarius Series is something of a subversion, as he speaks Greek, Ethiopian, and at least a half dozen other languages quite fluently, and enjoys Greek philosophy, but deliberately puts on a You No Take Candle dialect because he feels that he has an image to maintain.
In Harry Potter, house-elves obviously understand spoken English, but speak it in a grammar reminiscent of the way Afrikaans has evolved from Dutch, with simplified conjugations. In addition, most house-elves refer to themselves in the third person. They are, however, fairly intelligent creatures and are capable of more than most of the humans in the magical world seem to realize.
In Cerberon, when the eponymous unicorn from England takes human form and speaks in Aramish, it's pretty broken but not difficult to understand, while in English he can be very eloquent and occasionally poetic. The Prince of Aeronweyir, a dragon from Arumara, is noted to have the same ability to communicate telepathically as Cerberon, and understands what people are saying in English, but he avoids this trope by refusing to speak in the foreign language, using Cerberon to provide translations of what he says in Aramish.
Menelaos from Greek Ninja comes off as dumb due to his terrible English and the fact he rarely speaks because of that difficulty, but in Greek he can communicate normally. Eleonora, although fluent in English, sometimes resorts to speaking some phrases in Greek to him, often when she's frustrated.
From a Tortall Universe short story, Skysong the dragon is incapable of making human speech due to being just a baby; however, she's incredibly vocal in her natural dragon language when she gets to use it. Considering that she's as intelligent as any human, it annoys her to no end that people consider her a big, stupid lizard. When finally granted the ability to speak to humans, including her foster parents, she's over the moon.
Detective Max Hornung in Sidney Sheldon'sBloodline is so lousy at speaking either French or Italian others are unable to understand what he's trying to say. Some either take time to realize he's trying to speak in their language or simply need to be told.
In Amy Tan's The Bonesetters Daughter, LuLing's senile dementia is real, but when she speaks and writes Mandarin she's revealed to still be coherent much of the time — a lot more than she sounds in English.
In Heroes, Nathan 'Frying Man' Petrelli and other characters initially underestimate Hiro due to his poor Engrish. (Of course, even in Japanese he's still a geek…) This is also used to indicate where he is on his hero's journey. In the beginning, he's an utter loser, obsessed with comics, and his only plus is that he can stop time, otherwise, sucks to be him. Later, when he meets and falls in love with Charlie, he matures and grows, hence he learns better English. By the time he's completely fluent, he's a total badass and carries a samurai sword.
Happens at least twice in The Big Bang Theory: Ubergenius Sheldon is incoherent in Mandarin, and Raj claims he would kick Sheldon's ass in an argument if he was speaking his native language. Sheldon points out that English is Raj's native language.
Actually three times, since Sheldon learned Mandarin from Howard, who tried using it at their regular Chinese place.
Howard seems to overestimate his linguistic abilities. When he tells Penny she’s a ‘very beautiful girl’, his pronunciation leaves much to be desired, and the gang’s waiter at the Chinese restaurant referred to Howard as ‘the guy who thinks he speaks Mandarin’.
The Barney Miller episode "Hunger Strike" included an encounter with a middle-aged inmate (Nora Meerbaum) of an institution who had wandered off and taken some flowers from a street vendor. She cheerfully greeted everyone with the phrase "Noga ubav den" and offered the flowers, which she called "tsvet". Her supervising psychiatrist said it was "hebephrenic gibberish", but eventually it was identified as Macedonian, and a native speaker located in a nearby coffee shop (hey, it is NYC). She had been in the institution for thirty years because nobody could understand what she was saying. Unfortunately, this is Truth in Television.note It's based on David Tom, a Chinese immigrant who was hospitalized for TB, and kept in institutions for 30 years because no one knew his Chinese dialect. By the time he was rescued, he was insane. He won a lawsuit and spent the rest of his life in a Chinese-speaking nursing home.
Game of Thrones: Khal Drogo speaks very little of the "common tongue", and as such comes off as a bit of a savage. However, when we see the subtitles of his language, we see just how clever he really is.
Azure Bonds plays with extreme variant. "Strange funny lizard dude" walks through the first part as obviously sentient but not communicable and is taken seriously only as a warrior, especially after spoofed "First Contact" attempt. But when protagonists meet someone who can easily communicate with saurial, and old dragon first shows great respect to him and then informs his friends with whom they traveled, party is rather shocked (and remembers glaring evidence they dismissed). Later he learns thieves' sign language, though. Saurials speak in mix of sounds out of human ear's band and pheromone releases, so as long as some translation spell is not used they appears to be mute. Though nothing prevents them from learning to understand spoken Common... and Obfuscating Stupidity.
This happens quite a bit in Shadowrun since taking a language is ranked like a skill. A character's first language is listed as 'N' for native speaker, while any other ones are given a proficiency level. A character can have an astronomical set of mental attributes and still have a hard time conveying a concept in Farsi because she only has a 2 in it. One variant rule suggestion for dialects offers this trope as an idea. Instead of paying for the dialect in points, the player can get it for free in exchange for having a harder time with advanced concepts in the baseline version of the language. For example, a character could have "English (Cityspeak)" as a native tongue and be very hard to understand by people with just "English"
In Assassins, Giuseppe Zangara speaks-a in-a, how you say, a-fractured English. But during November 22, 1963, he switches to Italian and allows the other assassins to translate for him, revealing that he is extremely well-spoken.
Many of the Aboriginal characters in Bran Nue Dae. Somewhat subverted, as most of the Aboriginal characters speak English using very Aboriginal accents and slang words, which are sometimes seen by white Australians as being uneducated. We rarely hear them speak their native languages, presumably for access purposes.
The Trolls were originally homeless drug addicts. Most powerful of them, they most loaded up on highly addictive drug that slowly breaks down speech centers in brain. They still as smart as before, just cannot talk any better than this.
Some individual trolls, like Julius, are still fairly coherent and have an impressive grasp on the situation in The Hollows.
And if that made you head hurt, Teh S00p3rFR3ak speaks entirely in grammatically correct leetspeak.
Rikti: likewise speak: Rikti thought pattern. Translation device : Mark 1 : Sounds : completely idiotic. They've got a better grasp on pretty much every field of science but nuclear power than normal humans, and the more advanced translators or a Rikti breaking out of the thought pattern are capable of incredibly eloquent and detailed conversation.
Somewhat subverted by Lk'Onic, who gets an improved translator in the last mission and remains just as talkative as before. ("Mark 3 translator's pretty nice. Let's go.")
World of Warcraft does this at least once with a Murloc quest hub in the Borean Tundra. Well, it's not quite the same since we never hear them try to speak a language the players can understand, but when the player is magically given the ability to understand what they're saying, they're surprisingly eloquent. For example, during the quest "Grmmurggll Mrllggrl Glrggl!!!" which asks you to kill Glrggl, translates to: "he who swims against the tides of fate — eradicating the hope of life for all those who hear the siren song of death upon the waves!"
Some Draenei NPCs speak broken Common as well, understandable because they've only been on the planet for a few years.
It's also possibly the case for Troll NPCs, as Alliance players who talk to Vol'jin (who is typically characterized as quite intelligent) hear his response in less than fluent Common.
That line is something of a Genius Bonus for folks familiar with Russian idioms, as there is a Russian expression about weapon-safety that goes "Bullets are stupid and sightless". So he's actually calling his opponents blind idiots. Clever, Heavy, very clever.
There is an interesting version of this in Fallout 2. If you make a character with Intelligence less than 4, he is effectively, ahem, mentally handicapped. There is a character named Torr in one of the very first towns that is likewise handicapped, and normal players are unable to get much information out of him. Approach him with your own handicapped character and the ensuing conversation, while looking like two drooling men shouting random gibberish and nonsense at each other to the casual observer, is actually, when translated through the subtitles, a meeting of two great minds, with superbly polished manners and high level thought. Hilarity ensues.
This was used in Kasumi Todoh's plotline in Art of Fighting 3: She is searching for Ryo Sakazaki (who is a mixed-race American) in Mexico, and is using a Japanese-to-English dictionary to communicate. She naturally sounds demented in her win poses (and probably to any natives in the area, who don't speak English anyway.)
Alien visitor Meredy from Tales of Eternia is completely unable to speak English when you first meet her, only able to speak Celestian Melnics. Early on you participate in a quest to get her some Translator Microbes. This results in her speaking pidgin English for the rest of the game. However, once you are granted the chance to go to Celestia yourself you'll find that no other character talks like she does. She reveals herself to be quite the big cookie in the scientific research field once you get there, though.
Ivan Dolvich from the Jagged Alliance series originally spoke no English, but according to his in-game bio he took an "English as a second language" course between Deadly Games and JA2. His Russian is fluent and eloquent, his English is... comprehensible, barely. In the trailer for Back In Action his English is almost perfect, if heavily-accented; the games are a bit vague about how much time elapses between them, but presumably he's had time to practice.
Robert "Steroid" Gontarski might be another case. His grammar isn't perfect, he sometimes lacks basic vocabulary and has relatively low Intelligence (compared to other AIM mercs), but most of his "dumb muscle" image stems from his Ahnuld-type voice. The Polish version of Unfinished Business actually gives him a speech pattern which is completely different (since he is speaking his native language now), but still remains believable. If only they hadn't changed the voice...
Brother from Final Fantasy X isn't precisely eloquent in Al-Behd, but he at least uses proper grammar. When he starts trying to impress Yuna by learning her native language, he starts out exactly as one would expect: a limited vocabulary composed mostly of simple nouns and present-tense verbs. He gets better in the sequel, to the point that he could probably be considered functionally bilingual.
Any time a Japanese developer tries to speak English at a game conference like, say, E3, it always comes across as horribly forced and awkward, probably because they learned their lines phonetically. Some, like Hideo Kojima, use it to their advantage in really weird ways (Didjurikeit?) while others, like Shigeru Miyamoto, only do as little as they can get away with. When they switch back to Japanese they're obviously far more eloquent through their interpreters.
In No More Heroes 2, there's a brief cameo by an unnamed character who shows up out of nowhere, monologues in horrible, broken, monotone English, hands over a new weapon, and vanishes. The reason this character's English is so terrible? He's Takashi fucking Miike.
In Strong Bad's Cool Game for Attractive People: Strong Badia the Free, Homsar, who normally speaks in Word Salads, turns out to be quite eloquent when Strong Bad can (temporarily) communicate with him ("Why should my people risk open warfare for your considerable style?"). Strong Bad describes his 'eloquent' voice as being 'soothing', and Homsar will even get confused if Strong Bad tries to speak Word Salad back during this period. To others however, any conversation they hold is incomprehensible.
The Qunari are portrayed this way in the Dragon Age games, speaking in a stilted and overly-concise manner when they are forced to conduct business in Theodosian. As they strive for perfection in all things, the Qunari that the player interact with find their imprecise mastery of the language shameful, and express difficulty understanding words like "hero" and "cookie".
Unreal II: The Awakening has Ne-Ban, an alien who's the comic relief of the game, constantly mixing up words. The protagonist casually mentions it's because he speaks over fifty languages.
In Katawa Shoujo, when Hisao calls Lilly in Scotland for the second time in her route, he gets her mother, and makes an attempt to ask for Lilly in English before switching to Japanese; luckily, her mother also speaks Japanese well, and is willing to accommodate him. English also appears to be his worst subject, as earlier in the route, he got a 43 on an English test.
In Apollo Justice: Ace Attorney, Machi can speak English, but not very articulately, and for most of the trial, relies on Lamiroir to translate.
Suzi from Tales Of MU talks like a lolcats caption when trying to speak Pax, but she's a bit more eloquent in her native Yokano:
I do not see why we are forced to converse in the barbarous idiom of the coarse westerners even among ourselves. Why must we suffer the indignity of mangling our mouths with their disharmonious syllables simply because they have never taken the time to learn a proper language?
Oh, and when we say she talks like a lolcats caption, we're completely serious. Examples include "I can has cheeseburger?" and "I made you a cookie, but I eated it."
French That Guy with the Glasses reviewer Benzaie speaks pretty good English overall, but his thick accent ("Waddafuk? Dees ees boo-sheet!") is amusing enough that an entire video consists of his fellow reviewers affectionately mocking it. However, he has also done some serious videos in which he interviews French game developers in his native tongue. If you are used to his slightly mangled English, hearing him speak perfectly naturally can be a little jarring.
The title of the programming tutorial Learn You a Haskell for Great Good! invokes this trope, seemingly to put an approachable face on Haskell's strangeness (as compared to other programming languages readers may know).
SCP-811 doesn't exactly have a native tongue due to growing up in a swamp, but she does have complex thoughts and she gets frustrated at her difficulty expressing them.
Draak from Irregular Webcomic! is highly intelligent and has a rather keen grasp on complex ideas, like "quark" and "gene" (despite being in a medieval fantasy setting), but only speaks in mono-syllables. In his own tongue, he's quite eloquent.
Gunnerkrigg Court uses this briefly (in a reversal of how this trope usually works): As seen here (via the Translation Convention), Antimony's Polish isn't as good as her native English. Gamma is very shy and isolated because of not understanding English, but a veritable chatterbox with Zimmy.
Ed, in Digger, is capable of the deepest conversations and emotional moments of the cast. However, his grasp of whatever common language is being spoken is woeful due to the trauma of his exile and subsequent years of isolation. Other hyenas speak normally.
Occurs a couple of times in The Inexplicable Adventures of Bob!.Mook the Bigfoot is eloquent in his own language, but he talks in Hulk Speak when he tries to use English; his wife Goona is fluent in English, however. The Space Cop Officer Zodboink speaks several Earth languages but can't keep them straight, mixing words and expressions from different languages at random.
Yuki from MegaTokyo. On the other side of the language barrier, Piro speaks Japanese like a teenage girl, having learned it mostly from ren'ai games and shoujo anime and manga.
The Gragrum of Tales of the Questor tend to speak the common language in a rather mangled way, using heavily broken sentence structure, but once their leader speaks in his own language, his sentence structure and use of metaphors improve dramatically and excel many later human speakers. The Rac Cona Daimh around there tend to drawl too, but the single most capable lux user in the planet comes from there, and has the worst drawl of the lot, with many more practical and lux-efficient spells coming from near the swamps. On the inverse side, a well-spoken Rac Cona Daimh pastor speaking the Gragum tongue is easily outwitted in a short conversation to the point of pulling his trump card nearly immediately and arranges sentences oddly. When talking to humans, the fairly intelligent Rac Cona Daimh also often find themselves trying to describe a sense that few humans have and sounding slightly crazy.
Donovan "Little Pink Man in Pink" Deegan is only capable of speaking Orcish in the sense that he seems to have a rather large vocabulary. He just doesn't know what those words mean. When speaking his native Callanian (The "English" of the world) he is the world's most renowned poet and bard. It turns out that he speaks Orkish perfectly and acts otherwise because he thinks it's funny.
In The Cobra Days, The Sorrow is only just learning English. Occasionally when they're having trouble understanding him, one of the other Russian-speaking members of the Cobra Unit will tell him to switch to Russian, his native tongue.
Vaelia from Drowtales starts the story speaking next to nothing of the drow language, but improves over time and proves to be quite eloquent in her internal monologues and when she gets to speak her native tongue.
Done both ways in Gai Gin. The USA native Gin's Japanese starts out on You No Take Candle levels ("Aah ... eat tomato, and again you see tomato I ate. No wanna eat tomato?") and improves drastically over the course of the strip, though it gets worse again when she's emotional. Her Japanese boyfriend Pyon is slightly ditzy but perfectly intelligent, going into Badass Bookworm levels near the end when he researches frantically for a way to stop Gin being deported, but his English is hopeless: "Hi Daddy! Me name Pyon-Pyon!"
In The Law of Purple, Thud is a native of a jungle where people speak a different language than the rest of the planet. At one point he even informs someone that he's not stupid, he just has a thick accent.
Rio: (In Gardish) Ease, Xan. Patient be. We uses this for a vantage.
Xan: ... Your Gardish is terrible. We really must work on this.
General Ripper Luca from The Meek, shows a clear case of Spock Speak and some minor You No Take Candle issues, although the latter tends to come out more when he's upset. Word Of God is that's because the language being spoken at the time is Luca's third language, and sure enough, when Luca does speak other languages either in flashbacks or when talking to The Dagre, he uses contractions and doesn't make any speech flubs or grammatical errors.
Averted in Unsounded with Duane's generally loquacious and eloquent dialog. He's speaking in his third language.
The very German Professor Dementor of Kim Possible doesn't quite do the nailing of all of the idioms in English.
Stitch of Lilo & Stitch has elements of this, though normally seeming to be a Speech-Impaired Animal when speaking english. Especially apparent in the movie's conclusion, Jumba even commenting on him making a good argument. A single syllable good argument. He seems to be well versed in his native language's curses though.
Especially evident with educated people with Soviet (or even Russian) upbringing. Often, having received a solid courses in English (or having learned it themselves), they have rarely had an opportunity to practice it with native speakers. So, meeting foreigners for the first time (even non-English speaking, such as Dutch or Finnish or German), they tend to apologize profusely about their English.
Also done with native-to-native speakers, when describing or explaining something complicated, commonly the sciences, to another person who does not know what the more "intelligent" one is talking about. The terminology often used in their fields of study would be replaced with simpler words so that the other person won't get lost in the flurry of large and strange words. The journal Nature has been doing this successfully for over 100 years to explain research science things to scientists in other fields as well as to laypersons.
Particularly noticeable if one is speaking an uneducated, slang-filled version of a language vs. the other speaking a more educated version of the same language, having learned it in a class or from textbooks.
When Francois Truffaut played Claude Lacombe in Close Encounters of the Third Kind he was supposed to do some scenes in English, some in French. He went through the scene where he's yelling at the Army general about the "invitees", and Spielberg said that was good but he wanted to re-shoot the scene and this time could Truffaut speak English? It turned out he had been speaking English.
There used to be a common saying used by Ashkenazi Israelis when speaking Hebrew back when Yiddish was more popular: ‘It’s funny in Yiddish.’ Nowadays it’s usually, ‘It’s funny / it rhymes in Russian.’