Magical Incantation

"''"Darkness beyond twilight, crimson beyond blood that flows, ''Buried in the stream of time is where your power grows. ''I pledge myself to conquer all the foes who stand ''Before the mighty gift bestowed in my unworthy hand. ''Let the fools who stand before me be destroyed by the power you and I possess! DRAGON SLAVE!""

- Incantation of the Dragon Slave from Slayers

The most obvious way of getting the world to do what you want is by simply commanding it. After all, it works on people. However, telling rocks to get out of the way doesn't work very well. Clearly, we need to find the right words, magical words which force the rock to do as it's told. Such is the reasoning that has led to spells being associated with speech across the world.

The nature of the words varies from plain English, through dodgy rhymes and ancient languages, to unpronounceable by human tongue. The more normal the words, the more stringent the other constraints on casting the spell will be. Making the rock move by shouting "Move!" will usually require rare talent or considerable preparation; making it moving by saying "Fthagnchmthesgf fprnjklmpt fhqwhgads" merely requires extreme verbal dexterity.

When the Language of Magic isn't human, it's usually explained as either theurgy—angels and demons insist on being addressed in their native tongue—or true names.

The Great Big Book of Everything or Spell Book may contain incantations.

Specific examples of magic incantations include By the Power of Greyskull, Invocation, and many instance of Calling Your Attacks. Compare and contrast Words Can Break My Bones which is the usually shorter "words of power". Not to be confused with Invocation when this is done just for show. Compare Words Do Not Make the Magic for when the incantation itself is either irrelevant or else useless without the magical muscle to go with it.

Anime and Manga
"Darkness beyond twilight, crimson beyond blood that flows... I'll skip the rest. DRAGON SLAY!"
 * Yuki Nagato from Haruhi Suzumiya uses incantations, in the anime they are sped up and backwards Microsoft SQL scripts.
 * In the books, they're simply SQL.
 * In the Nasuverse, most magic doesn't require incantations (although many mages use them, apparently as a form of self-hypnosis that makes channeling mana through one's body easier), but there are two separate cases where the words do matter. First, in Kara no Kyoukai:, there's someone who learned to talk to reality, and can change it by describing the world differently than it is. Second, there's Caster in Fate/stay night, who uses the language of the Age of Gods, which is apparently such that the words themselves can are fully-formed spells. Also, it's impossible for modern humans to speak it for whatever reason.
 * High-level magi can also shorten their incantations, most notably with Notarikon. The most extreme is Cornelius Alba, who can incant eight lines in under two seconds and create a thousand-degree flame.
 * Magic in Slayers requires an incantation of at least the name. Whether the full incantation of a spell is required seems to be based on whatever flows better in the show, but powerful spells NEED the incantation (Lina's big three spells are never cast without incantation, except when she used Dragon Slave to comically abuse Gourry.)

"Tiara: "Powerful subjects, show me the source of your powers. Fulfill your contract with Tiara! Bring forth the powers of the ancient scriptures and place them upon the name of Tiara. Fulfill your contract! Geil Eldo Samath!""
 * The official explanation is that the Chaos Words (in-universe term for the incantation) are needed for the full power of a spell, but the spell-caster can skip the incantation to get the spell off faster if they're familiar enough with it.
 * Mahou Sensei Negima does this in Latin, Ancient Greek, Sanskrit, and so forth, requiring at least an activation key word/phrase before each spell, then the incantation itself. Its possible to use magic without one for speed/surprise, but the spell will be less effective. Also notable is that the spell after being spoken can be held for approximately 20 sec, giving the wizard a greater ability for surprise. Unincanted, delayed, and fully incanted spells can themselves be stacked atop others of their own kind, and eachother as well, leaving little limitation to the wizard besides their Mana pool and skill.
 * Incantation length is, to some extent, a central part of the series' mechanics. Because spells cannot be cast with incomplete incantations, mages often pair up with frontline fighters so that the opponent's fighters can't attack and interrupt the mage's spell. Incantation length was also a deciding factor during Negi's fight with Chao; Chao attempted to cast a very powerful spell, but its incantation was too long, and Negi was able to fire off a powerful spell of his own before she was able to finish.
 * While most spells in Magical Girl Lyrical Nanoha don't acquire this, Status Buff types like the ones that Caro use, and some high-level magic such as pretty much everything that Hayate casts and the Thunder Fall spell Fate used to activate the last Jewel Seeds, require chants of varying length. It also depends on the caster; while Nanoha never uses an incantation for Starlight Breaker, the Book of Darkness does.
 * This is a very strange case for Nanoha. Even the title references her need to use an incantation (Magical Lyrical) which is summarily dropped after the 2nd episode and for some reason never brought up again though it remains part of the title for all 3 seasons. Very odd.
 * Spells in Record of Lodoss War are cast using an incantation that's essentially a rhyme describing the intended effects.
 * In Ojamajo Doremi, all the witch apprentices have a specific set of magic words they have to speak before giving a command (e.g. Doremi's is "Pirika Pirilala Poporina Peperuto"). In the 4Kids dub, however, the girls chant a rhyme describing what they want to happen.
 * Kidou in Bleach. Bonus points for the incantations being mostly incomprehensible gibberish. If a user is sufficiently familiar with a particular kidou, they can skip the incantation and recite just the spell's name and number. Just to clarify, the words themselves are fine. But they're put together in ways that sound like mistranslated metal lyrics. See quote page for an example.
 * Scrapped Princess has these. More adept magic users can abbreviate the incantations to cast spells rapid-fire: makes for a funny Curb Stomp Battle in the first episode.
 * Shamanic Princess reserves its longest incantations for transformations.

""Realm, Realm, the light that fills the Magical World, as a sign of protecting the foreign world, grant me power!""
 * Heikas, heikas. Estai, bebroi. Zazas, zazas. Natasatana zazas...
 * Cardcaptor Sakura has her card sealing incantations together with her magical baton.
 * Mahou Tsukaitai uses funky gibberish as incantations that are strangely Ear wormy...
 * In Zero no Tsukaima, all spells require incantations, which are actually composed of random names of runes from the various runic alphabets, especially the Elder Futhark.
 * Oku-sama wa Mahou Shoujo has "Magity", which is enough for simpler spells. For transformations and larger spells, something longer is required:

Fan Works

 * In The Arithmancer, a Harry Potter fic by White Squirrel in which Hermione is a mathematical and arithmantic prodigy, the number of syllables in an incantation are dictated by the mathematics of the spell, and the words can be in almost any language as long as they describe the spell's function in some way. Hermione creates spells in Dog Latin, real Latin, Spanish and several other languages (even English!), and in one case improvises a color change spell in a pinch by solving the math in her head and then coming up with a Dog Latin phrase that matches the number of syllables it calls for.

LARPs

 * In fantasy LARP systems, particularly those based off of NERO, the success of a spell depends both on correctly reciting the incantation (along the lines of "I call upon Mystic Force to cast Fireball!") and hitting your target with a spell packet (aka a beanbag).

Literature
"he whispered dark names and grisly incantations forgotten the world over save in the grim hinterlands of dark Stygia, where monstrous shapes move in the dusk of the tombs."
 * Harry Potter spells are mostly in Latin Latin-ish.
 * Magic in Earthsea works by the user speaking the language of dragons; since it is impossible to lie in said language, the universe will change to make what is said true.
 * In Piers Anthony's Apprentice Adept series, all Stiles's spells have to be in rhyming verse. Slightly complicated by the fact that each incantation only works once, ever.
 * Magic from the Eragon series must be cast by speaking your intentions in the ancient language. It used to be merely a matter of willpower, but the elder race realized that leaving magic up to your concentration tended not to go well, so they fixed it.
 * In Hugh Cook's Chronicles of a Age of Darkness, the wizards use a non-human language, in which every single verb is irregular.
 * In the Kate Daniels series by Ilona Andrews, words of power are acquired by mages having a contest of wills against the words when first encountered. Success means you acquire the word, failure means you die. These words are extremely powerful, and almost impossible to resist, until Kate encounters a bad guy whose native tongue is the ancient tongue from which the words are taken...
 * In Poul Anderson's Operation Chaos, the incantations require an exotic language. The narrator explains this as similarity: you can not expect anything but ordinary results from using ordinary language. He has not master much of language, but he whips together an incantion in Pig Latin.
 * The Dresden Files has many interesting examples. Each wizard can attach a meaning to that particular word. However, if they attach a meaning/spell to a word that they use often (e.g. fire) it could be messy. Thus, wizards generally use a language that they are not intimately familiar with, or they use a bastardized version of a language.
 * Rituals, a type of spell that can be done by non-wizards by calling on another entity, do seem to require a specific form of words.
 * The Philosophical Strangler by Eric Flint plays this for laughs; the Rosy finger takes so long to cast that the fight is already over when it's done.
 * In The Belgariad by David Eddings people use the "Will and Word" to cast spells. They concentrate on what they want to happen, and speak. What they actually say doesn't matter, and Garion once gets told off for using "Push" to move a rock - not because it didn't work, but because wizards lose respect if they going around telling things to "push" or "flop".
 * In his "Tamuli" and "Elenium", a mage or wizard is expected to ask the god of his choice for assistance in their particular language, but Sparhawk seems to be able to get away with fudging this at least once through his particularly close relationship with one of the gods.
 * In Robert E. Howard's Conan the Barbarian story "The Phoenix on the Sword", Thoth-amon uses this.


 * Magic users in The Lord of the Rings sometimes use incantations and sometimes don't- exactly why is never made clear, though as a professional philologist Tolkien certainly had respect for the power of language. Some individuals, such as certain elves and Maiar, uses songs instead.
 * How spells are cast in The Witches of Bailiwick. They usually take the form of a little rhyming poem about 3-5 lines long, although more powerful ones can be really long.

Live Action TV

 * "Lo lo, Bromios. Lo lo, Dendrites. Lo lo, Eleutherios. Lo lo, Enorches."
 * On Supernatural Latin and Enochian appear to be the languages of choice for the banishment of both angels and demons.
 * In the 1998 Merlin series, this sort of magic is used by the lowest class of wizards, Voice Wizards, or wizards by incantation. Stronger wizards use gestures, or perform magic simply by thought.
 * All witches and demons in Charmed can cast magic as long as their words rhyme or is in some form of poem like a haiku.
 * In Star Trek: Deep Space Nine, these are used for summoning the Pah-Wraiths.

Tabletop Games

 * Dungeons & Dragons (other than Original and 4 ed. where it's not specified) has spells using three components, of which Verbal is absent least often (granted, for spell like dispel silence or vocalize it's kind of the whole point) and the only one most often. And then there are Power Words, where it's condensed. Bards and Song mages by definition have to sing for any spell, with a few exceptions when playing an instrument is enough.
 * 3.x got all metamagic converted into feats, so any spell can be muted with Silent Spell feat.
 * Forgotten Realms approach, was also not given in details, but for the curious, clarified via the fan site is that usually incantations are arranged as couplets ending with "abracadabra" word triggering the effect. That's easy to remember and concentrate upon, as well as showy, of course. Activation words for items are almost always "abracadabra" type, for obvious reasons. According to Volo's Guide to All Things Magical, after the fall of Myth Drannor there was a fad of crafting items so that their activation words could be concealed in a normal phrase, but it, uh, died out (though not without leaving some dangerous legacy behind).
 * In Warhammer Fantasy Battle there are arcane languages that must be used to cast spells.
 * Early editions of The Dark Eye had actual short rhymed incantations with every spell for the players of spellcasting characters, with a literal "if you don't say it, your character doesn't cast it" approach. To this troper's understanding, this was gradually phased out later.

Video Games

 * Final Fantasy Tactics all manner of spell casters will sometimes call out an incantation (such as "Aurora, exhale bloody air! Dark Holy!") The catch is that the incantations appear at random. You can generally pick out a player's favorite class because they'll have certain incantations burned into their memory, due to using the spell enough to see it frequently.
 * Sadly, this was removed entirely from the remake.
 * Valkyrie Profile and its sequels are full of these when big magic is performed by a spell-casting character or even some of the bosses. Bloodbane's rendition of Gravity Blessing is an incantation of pure horror. Celestial Star, quoted in the quotes section, is the most well-known because it delivers the most hits in the first game.
 * In the Tales (series), spells seem to require this. The more powerful the spell, the longer the verbal incantation is, in most cases. However, the incantation can vary between different casters, implying that this is more to help the caster focus than to actually shape the spell.
 * Although it's subverted in Tales of Vesperia if Rita is in Super Mode, when she'll literally say "Blah Blah Blah" followed by the spell name.
 * The Power of Words in Yggdra Union and Blaze Union is an insanely powerful, face-meltingly rare ability that essentially lets the user play with reality using only magic and self-created incantations. There's only one person who's ever mastered it in the realm of Ancardia (that would be ), and the hell that said person went through to master it ought to be enough to discourage anybody else from trying. The general-use magic system in Ancardia, Tactics Cards, was set up by the Power of Words but can be used by any character via Invocation.

Web Comics

 * In The Order of the Stick, the verbal component of casting any spell is simply saying the name of the spell, as per the D&D rulebooks. For metamagic feats, the feat's name is appended to the spell's. For spells with a long casting time, the name is repeated over and over.
 * Actually that's a mild parody more than anything else. It is true the D&D rulebooks before 4th edition (where from memory the issue seems to be dropped) do specify which spells have verbal components (because it could be relevant for gameplay - eg if your character is caught in a silence spell or gagged or similar), but it isn't specified what the actual words are. If you were interested in that sort of thing I suppose you could make up and actually say 'words of power' for specific spells but the usual procedure is just to tell the DM 'my character casts spell X', and it is assumed your experienced wizard or whatever your character happens to be knows what to do. Incedentally, for those unfamiliar with the system it is worth mentioning that the magical incantations aren't strictly necessary in 3rd edition, you can cast spells without them. However your character must be trained to do so and the spell counts as being one level higher than it otherwise would have.
 * In Sluggy Freelance Gwynn's spells sometimes require her to speak a Language of Magic that's written in bizarre letters no one outside the strip has any clue how to pronounce. The Harry Potter Expy wizards, however, use Canis Latinicus.

Web Original

 * In the Whateley Universe, there seem to be a number of ancient (read: dead before humans used sticks) languages that work for magical incantations, as well as more modern (human) languages. Fey has used the language of the Sidhe.

Western Animation

 * In Gargoyles, spell incantations were in Latin, unless the caster was one of Oberon's Children.
 * or from a different magical tradition like the Jewish/Kabbalahist in 'Golem' or the Emir in 'Grief'. They used incantations in Hebrew and English but the Emir's incantation referenced Egyptian deities. Also, a caster of significant power could use one-word incantations, like the Archmage with the Eye of Odin, Phoenix Gate, and Grimorum Arcanorum all adding to his power.
 * Word of God is that certain languages, such as Latin and Hebrew, are simply better for this sort of thing than modern English (at least if you're a mortal wizard- Children of Oberon don't seem bound by language and just say what they want to happen, usually in rhyme).
 * In Visionaries: Knights of the Magical Light, the power of the magical staves are called upon using Magical Incantations in the form of poems.
 * Raven uses many of these in Teen Titans. One of the more memorable ones is: "The gem was born of evil's fire. The gem shall be his portal. He comes to claim. He comes to sire. The end of all things mortal!"

Real Life

 * Enochian, an alleged "language of angels" recorded in the journals of 16th-century mathematician, astronomer, astrologer, and occult philosopher John Dee, which is central to the practice of Enochian magic, a variety of Theurgy that incorporated ceremonial elements reminiscent of Hermetic magic. It was later expanded upon by a number of other occultists, including Aleister Crowley.
 * Several authentic "spells" survive in old European documents, including For a Swarm of Bees (an Anglo-Saxon metrical charm that was intended for use in keeping honey bees from swarming), the Nine Herbs Charm (a charm intended for the treatment of poisoning and infection), and the Merseburg Incantations.