- "Harry aimed his wand at Peeves and said, "Langlock!" Peeves clutched at his throat, gulped, then swooped from the room making obscene gestures but unable to speak, owing to the fact that his tongue had just glued itself to the roof of his mouth."
- —Harry Potter's use on Peeves the Poltergeist in the Hogwarts hospital wing[src]
Langlock is the incantation to a jinx that causes one's tongue to affix to the roof of their mouth. It is known to work on wizards as well as on ghosts (including a poltergeist, like Peeves). It was most likely invented for the sake of preventing someone from speaking aloud or even to prevent a spell from being cast.
It was invented by Severus Snape and recorded in his copy of Advanced Potion-Making while he was a student at Hogwarts School of Witchcraft and Wizardry in the 1970s. Harry Potter used Langlock on Argus Filch twice during the 1996-1997 school year "to general applause", and again on Peeves.
Behind the scenes
- It is unknown when Severus Snape invented this and many of his other spells as according to Sirius Black "he knew more curses when he arrived at school than half the kids in seventh year." 
The word langue is the root for tongue, while lock is an English word.
Notes and references
- ↑ Harry Potter and the Half-Blood Prince - Chapter 12 (Silver and Opals)
- ↑ Harry Potter and the Half-Blood Prince - Chapter 12 (Silver and Opals) - "Harry had already attempted a few of the Prince’s self-invented spells."
- ↑ Pottermore - All about... Severus Snape
- ↑ Harry Potter and the Goblet of Fire - Chapter 27 (Padfoot Returns)