In the Harry Potter series, are wizards capable of creating their own spells, or are they limited to the spells that they're taught/learn? I seem to remember something about Snape creating sectumsempra, but I'm not sure if that really is the case.
As @OghmaOsiris has said, spells can certainly be created, though the means of doing so is unclear.
There's also quite a simple example as early as the first book: Harry vanishes a pane of glass for a few minutes, allowing a snake to escape.
We can also postulate a process for spell creation from the sixth book: Harry sees several words before Sectumsempra, all of which are crossed out. It's possible that the process of spell creation involves focusing on the effect you want, discovering a word tied to it (I'm unclear as to how this would work, except that Snape obviously knew the general sound of the word), and refining it until you find the most effective word.
This is borne out somewhat by the early books: casting the spell Wingardium Leviosa, slightly improper pronunciations (and slightly incorrect wand movements) still produce something like the intended effect.
The other problem is wand movements -- there must be some form of standard movements, which can be used to cast most spells. There must also be a form of notation for wand movements for when the standard ones aren't correct. We can assume that Snape's Sectumsempra spell used the standard movements (possibly the standard 'attack spell' movements).
In the Half Blood Prince, Severus Snape created his own spell, Sectumsempra, which created invisible swords that cut the enemy.
Voldemort also created his own spells for his death eaters - the Dark Mark, for example: Morsmordre, as used in the 4th movie.
I imagine that wizards and witches at the level of competency as Voldemort and Dumbledore could come up with their own spells on the fly. The battle at the Ministry comes to mind. I doubt that those were already composed spells, but were the raw magic manipulated by Dumbledore and Voldemort.
I get the idea that spells can be created by wizards from Order of the Phoenix, when Luna tells Harry about her mother's death. When Harry asks her if she's known anyone who's died, she responds
"Yes, my mother. She was quite an extraordinary witch, you know, but she did like to experiment and one of her spells went rather badly wrong one day. I was nine."
This makes it sound as if Luna's mother was able to create her own spells, or at least attempt to do so with limited success.
Harry thinks at first that many spells in his copy of "Advanced Potion-making" were invented by the Prince because they've been crossed out and re-written, but then when he talks to Lupin about "Levicorpus" Lupin makes it sound as if that spell was merely popular during his time at Hogwarts, and wasn't invented then. However, when Harry attempts to use "Sectumsempra" against Snape, he says
"No, Potter! You dare use my own spells against me? It was I who invented them--I, the Half-Blood Prince! And you'd turn my inventions on me, like your filthy father, would you?"
So, clearly, Snape actually did manage to invent his own spells while he was at school.
We also learn from Mr. Ollivander that wizards are able to conduct their magic through many magical objects, and you will simply get the best results from a wand that has chosen you. Think of the sparks that Harry makes issue from his wand when he first tries it in Ollivander's shop; that wasn't a particular spell, because he hadn't learned to produce sparks with a spell yet. Magic doesn't always have to be in spell form, and the sort of magic that underage wizards and witches are able to produce before they come to Hogwarts is often individual to each person. I would think that with enough study of magical theory, individuals would be able to harness this sort of magic and recreate it with their own incantation.
We know that potions are invented over the years because the Wolfsbane potion is said to be a recent invention by Lupin in Prisoner of Azkaban. The chocolate frog card about Dumbledore notes him for his work on alchemy with Nicolas Flamel. This gives the idea that there is new magical research and innovation within the wizarding world and people are always learning new ways to channel magic, so I think that spells can be created with enough work and trial and error.
From the Harry Potter Wiki, on the article Unlocking Charm: (Alohomora)
J. K. Rowling stated that the word was from the West African Sidiki dialect used in geomancy and has the literal meaning Friendly to thieves.
Likewise, Accio comes from the Latin "I call" or "I summon". Almost every spell in the Harry Potter universe with an article on the Wiki has an Etymology section that explains the origin of the name.
For a third example, Sectumsempra was mentioned in the question, and is made from the Latin words sectum (cut) and semper (always).
From the examples, it is reasonable to assume that spells are actually just a subset of language, that are capable of achieving effects when combined with wand use by a witch or wizard. Achieving most of the desired effect even with a slight mispronunciation also gets explained away, as accents cause different pronunciations even with two people who speak the same language.
I don't think spells are actually created, they are discovered. But as other people have noted there's a dearth of details on this topic, so there's not much evidence either ways. But a possible scenario seems to be that spells are based on some core principles, and it's more a matter of people finding out what combination does what.
I do seem to recall that potions are 'invented' (instead of 'discovered'), but I can't say for sure.
I think it has to do with the relationship between INTENTION and FUNCTION. The wands are clearly sentient/intelligent to some degree ("choosing the wizard" implies that they are capable of choice). As wandless magic can be done (demonstrated once or twice by Dumbledore, I believe) we can more or less rule out magic's "motive force" being based in the material of the wand. Instead, it stems somehow from the individual, and things like saying spells, wand movements, and even the wand ITSELF are just focusing devices, there to make you think in a certain way and with a certain intent.
Therefore, one can guess that the process of spell creation is quite similar to theatre, in a way. Movements and words that capture and create a certain emotion/ intent in those who perform them.
Yes, they can.
- When Harry is trying to tell everyone about have gold fire spewed out of his wand at Voldemort, which saved him, they tried to tell him that sometimes wizards accidentally find new magic.
- There was something in charms class about some wizard who mispronounced a spell and ended up with a buffalo on his chest.
- In book six, after breaking up with Lavender, Ron accidentally makes it snow.
- Harry one time got mad and sent sparks out of his wand (accidentally) and burned a hole in the carpet.
There are many more instances of things like this, but that just means that, yes, wizards can create spells. How do you think they got the ones they use now?
In Harry Potter magic seems to be an extention of a wizards feelings. The words and motions are simply a way to bring forth the feelings which are then channeled out of the wizard. Once a wizard has deteremined how to bring about this feeling consistantly they can others. Thus some spells can actually be cast with out motions or words but evoking the feeling and channeling it out. This is hinted at in the first book pretty extensively and talked about in the Room of Requirement lessons in the OOP. While the book does not outright say this is how it works, all of the writings lead me to believe it.
I always thought about spells as a junction of words + will power + runes (movements)
- Simple words create simple commands, match words and create complex spells. (Like Snape's song-like incantation recovering Draco from sectumsempra)
- Will power, and Focus, the intentions need to match with your words.
- Runes for movements, the study and translations of runes to create the desired movement based on it's "writing on air" (I'm not sure about this, but I think Harry had to study runes to learn Accio, for the first task in book 4)
of course this is all fanfiction, but based on what we got from the books.
I believe previous theories about using a different language, like for example Latin. I think the incantations are like a command to the wand, telling it what effect to invoke; I get this from whenever someone buys a wand - they don't choose the wand, the wand chooses them. You wouldn't necessarily need to be a Dumbledore-level wizard to come up with spells on the fly; as long as you spoke Latin or some other related language (do any of the spell names have Greek origin?) you could come up with anything really; for example, the spell 'Reducto' comes from the Latin word meaning "back," so say I wanted it to repel something faster the further it went, I might say "Auctificus reducto," meaning literally in Latin,"Increasing back." Several other incantations might work, for example "Propulso" may work as well as Reducto.
Probably not too different from computer programming. Putting together other spells (as subroutines) to create the desired effect. For example, to make a food spell you'd probably use spells like 'accio ingredients', 'aguamenti' and 'incendio'.
I imagine the incantation word as a pointer to the magical instructions. The actual word doesn't matter (the spell creator can choose it), but they're often Latin-like words by convention. The function to create a new process is CreateProcess on Windows, but it could be sggfafesojtg. It's just easier to remember that CreateProcess creates a process. In the C standard library the function naming convention is shortened English words, like strcat, strcpy, malloc.
Voldemort invented the taboo in the seventh book:
“Sorry,” said Ron, wrenching Harry back out of the brambles, “but the name’s been jinxed, Harry, that’s how they track people! Using his name breaks protective enchantments, it causes some kind of magical disturbance — it’s how they found us in Tottenham Court Road!”
This must be a new spell, because:
‘My dear Professor, surely a sensible person like yourself can call him by his name? All this “You-Know-Who” nonsense – for eleven years I have been trying to persuade people to call him by his proper name: Voldemort.’
Professor McGonagall flinched, but Dumbledore, who was unsticking two sherbet lemons, seemed not to notice.
‘It all gets so confusing if we keep saying “You-Know-Who”.’ I have never seen any reason to be frightened of saying Voldemort’s name.’
If the Taboo spell existed, Dumbledore would have known why there are reasons not to say Voldemort's name (even if it hadn't been tabooed yet, it's still something Voldemort could've done.)
Yes, spells must be created, or else if it is not created, no spells will ever exist. Spells cannot be discovered without being created.
I suspect, however, there may be an age limit on creating spells, any wizard who is under the age of seventeen cannot learn how to create their own spells, and believe it or not, once a spell is created, it cannot be reversed back to non existence. Just like disposable CD/DVDs, once you have burned data in there, you cannot wipe the CD/DVD blank. The worst part of Spell Creation is that if the wizard who creates the spell forgot the incantation or the movement, their effort of creating a spell is wasted. Therefore, when a wizard creates their own spell, they should first write it down, keeping a record of it, so if they forget, they can go back and check.