Hollywood Spelling

No, not Aaron. Or Tori.

In television and movies, due in part to The Law of Conservation of Detail, no matter how many ways to spell a name there are, the person in question will always spell it correctly, first try, even if only told the name over a telephone or even a bad radio transmission. This includes slang words, given names, surnames, chemical names, astronomical names... there is never a need for a spell-chequer in Hollywood.

Many given names and surnames can also be legitimately spelled in various ways (Claire, Clare, Clair...) and are seldom disambiguated. The situation gets especially Egregious when the name is an example of Psmith Psyndrome or My Nayme Is...

Anime and Manga

 * Averted a few times in Death Note because it's relevant to the plot and because Japanese contains a very high number of homophones. (When Misa learns the kanji of Light's name, she spends much time wondering how it is pronounced.)
 * Greatly complicated by the fact that Light's name is Gratuitous English instead of a standard Japanese name.

Comic Books
"Spell those. You're on your own."
 * Averted in the second issue of Cable & Deadpool: Cable phones Irene, a friend of his on the Daily Bugle, and asks her to look up three would-be anarchists with complicated names.

Film

 * The Bourne Identity features a telephone call to a hotel asking after the guest "Jason Bourne", without offering any alternate spellings (like Borne).
 * Although it's averted a moment later, when the same character asks after "John Michael Kane" and then specifies "Kane with a 'K'".
 * Kiss Kiss Bang Bang averts this when Perry briefs Harry on their assignment giving the name of his client as "Allison Ames, A-M-E-S."
 * There's a scene at the end of the film The Cowboys, where a man is being commissioned to make a gravestone. Despite never asking, he somehow knows how the name on the stone should be spelt (it's a fairly common name, spelt in an unusual way).
 * Inverted in Bill and Ted, when Abraham Lincoln clarifies to a cop how his surname is spelled. Whilst in full 'Abraham Lincoln costume'.
 * In the "Syfy original movie" Scream of the Banshee, two characters watch a video clip of a man who mutters something that sounds like "bean see." One of them jokes that it might be Spanish for "beans, yes" but the other promptly types it into a search engine and - in about two seconds - informs him that it's Gaelic for "banshee." The problem with this is that the "see" part of that Gaelic term is spelled "sidhe", and "bean sidhe" is in any case pronounced "banshee". There's no way she could have Googled it that quickly (if at all) if she didn't already know that.

Literature

 * The English translation of the novel Rasen lampshades this as a plot point: Ando unconsciously writes down the kanji for "Asakawa", and Mai realises that she's never learned to spell the name.
 * Used as a plot point in Agatha Christie's The Secret Adversary, featuring Tommy and Tuppence. A note allegedly written by Tuppence is shown clearly to be a forgery when her name is misspelled "Twopence". Not only that, but Tommy is able to identify the novel's culprit based on the misspelling, because one of the two main suspects had seen Tuppence's name written down while the other hadn't.
 * Note to non-Brits or to younger British readers: "twopence" is pronounced in the same way as "tuppence", especially when it refers to "old" (pre-decimalization) money. "Tuppence" is an informal spelling imitating the pronunciation. Someone hearing the name of the heroine but not knowing how it was spelled might very well think it is spelled "Twopence".
 * Averted in Stephen King's The Green Mile, where John Coffey, whenever having to tell his name, always clarifies that it's not spelt "like the drink".
 * Averted in L. M. Montgomery's Anne of Green Gables series. Anne often introduces herself as "Anne Shirley. Anne--spelled with an E", to ward off those who would mispell it.
 * In Memoirs of a Geisha, the main character notices someone spells her name wrong, but doesn't correct him.

Live-Action TV

 * An episode of CSI: Miami involving a "Black Dawg Productions".
 * The Lone Gunmen had a character named Yves Adele Harlow, which the Gunmen discovered was an alias, because it's an anagram of Lee Harvey Oswald. Her name was never spelled out until they made the connection, despite there being at least four different ways to spell the names involved. For one thing, 'Yves' is usually a men's name, and is pronounced exactly like the women's name 'Eve'.
 * On the same note, The X-Files, constantly. The trope is further highlighted by the deliberately odd names possessed by apparently everyone in the X-Files universe. (The cast of new characters in the movie, for instance: Alvin Kurtzweil; Ben Bronschweig; Jana Cassidy; Darius Michaud; Conrad Strughold.)
 * Doctor Who (the new series) averts this trope - multiple characters introduce themselves by pointing out a spelling eccentricity with their name (Lynda-with-a-Y, Tallulah, three Ls and an H...)
 * In Torchwood: Children of Earth Ianto (manning the computer) is instructed by Gwen to search for a person called "Clement McDonald", but with the note to try both Mc/Mac spellings as she only heard the name spoken, not written down.
 * And again in the eighth episode of Torchwood: Miracle Day. When getting info on the mysterious three families, the CIA analyst asks them for the spelling of the names.
 * Nobody in the recent series The Invisible Man ever mistook Darien Fawkes for a Darian Fox. (Though to be fair, they are occasionally pronounced slightly differently, depending on the speaker's accent)
 * Or Darrien, Darian, Darrian, or Derrien.
 * Inverted in the Monk episode "Mr. Monk and the Election", where a threat letter addressed to Natalie Teeger misspells her last name (forgetting the R in her last name). This turns out to be a Chekhov's Gun.
 * There was another episode where someone pronounced her name wrong while reading it off a piece of paper and she corrected him.
 * Used in another recent episode, where someone misspelled Natalie's last name on a package containing a (this time, with an A instead of a second E). Again a Chekhov's Gun, when Natalie notices that the same mistake is made
 * Averted on Lost. When Hurley takes his census, he confirms the spelling of Ethan's last name (Rom, not Rahm or Rohm) before writing it down. Of course, this is so the audience can figure out that "Ethan Rom" is an anagram of "Other Man."
 * Not a name, but a minor plot point in the first series finale of Life On Mars involves a man's last word being "key"...or possibly "quay."
 * In Greek, Lizzi points out that her name is spelled "With two Zeta Beta Z's!"...but neglects to mention it's spelled without an e.
 * And with an i instead of a y.
 * On one episode of Seinfeld, George tries to impress people with his uncanny ability to guess how their names are spelled. When he tries it with the head of the TV network they're trying to impress, he's coldly informed that he's "not even close."
 * Averted in Buffy the Vampire Slayer. When Buffy realises that recurring villain Ethan Rayne is in town again, Riley phones the Initiative and asks for a search on hotel registrations matching his name. "Ethan Rayne, R-A-Y-N-E." (Probably intentional: the entire sequence is about contrasting Riley's down-to-Earth soldier demeanour with Buffy's supernatural methods.)
 * In an early episode of Stargate SG-1, O'Neill is adamant about the correct spelling of Teal'c's name, including the apostrophe. This despite the fact that Teal'c himself comes from a culture that doesn't seem to use the Roman alphabet, and the episode takes place before he's learned practically anything about Earth culture. You wouldn't think his name would even have a standard spelling yet, let alone such a weird one.
 * O'Neill constantly insists that everyone, including aliens, spell his name with "two L's", which is a Shout-Out to the fact that the character's name in the original film was spelled with one L, and also the fact that Richard Dean Anderson is nothing like Kurt Russell.
 * They also in one episode insist on the correct spelling of "Goa'uld", despite the fact that they never pronounce it correctly.
 * Comes up frequently on Without a Trace (a show on which - at least in the early seasons - the writers often seemed to forget that the main characters don't actually get to see witnesses' flashbacks or receive copies of the script) but a particularly egregious example was in an episode where a witness tells detectives about an African activist and then, upon returning to headquarters, one of them tells someone who wasn't present when the man was first mentioned (so even if the witness spelled the name off camera it wouldn't matter) to search for him in the FBI records. The detective promptly types the name in and rattles off the details of the man's life. The camera then shows the screen the detective is reading. This is the point at which the viewer realizes that the man's name is "Adisa Teno" and not "Adis Ateno," which is how everyone has been pronouncing it to this point.

Video Games

 * Used as a plot point in the video game Phoenix Wright: Ace Attorney: Justice for All. In the first case of the game, a key piece of evidence is a message scrawled on the ground, apparently by a murder victim. The message is the word "Maggie", and the prosecution claims he was identifying his killer as his girlfriend. Phoenix realizes the message was not written by the victim, as the accused spells her name Maggey, and if anyone knew how she spelled her name it would be her boyfriend.
 * Critical to the plot of Heavy Rain is that.
 * Kingdom Hearts: Birth By Sleep has a weird example - Master Xehanort's plan is to create a superweapon with a Punny Name: . This confuses Ventus, and Xehanort actually interrupts his supervillain speech to clarify, even conjuring a glowing letter as a visual aid. This explanation is only offered in Ventus's storyline, however - in Aqua and Terra's, it's almost like they can read the subtitles and pick up on the difference themselves.
 * George Stobbart of Broken Sword is fond of introducing himself as "Stobbart - George Stobbart. That's two b's, and two t's". This tends to just confuse people, as while there technically are two t's, they're separate.
 * Averted in Mass Effect 2. At one point, Shepard will receive a message from a prisoner he/she shot at during a prison riot. The prisoner spells his / her name "Shepherd".
 * Of course, judging by the spelling of the message, the prisoner was slightly illiterate.

Western Animation

 * On one episode of Teen Titans, Jinx immediately (and excitedly) spells her name when her idol, Madame Rouge, asks for it. May count as a Fandom Nod, since many fans had been erroneously spelling it "Jynx" (like the Pokémon) instead.