Parselmouth

A Parselmouth is the term for a witch or wizard who possesses the rare and unusual ability to speak Parseltongue, the language of serpents and other magical serpentine creatures like the Basilisk and the Horned Serpent. The ability is typically innate and hereditary, and those who possess it are often unaware that they are not speaking a human language when conversing with serpents. For the speaker, Parseltongue sounds like a normal language, but to all other listeners, it manifests as a series of strange, sibilant hisses. Harry Potter himself was unaware he was a Parselmouth until his second year at Hogwarts, believing he was simply understanding the serpents' thoughts. The ability allows for not only communication but also a degree of control over serpentine creatures. While not inherently a Dark Magic, the ability to speak Parseltongue is widely feared and distrusted throughout the wizarding world due to its strong association with Dark Wizards, most notably Salazar Slytherin and Lord Voldemort.

The most famous Parselmouth in wizarding history was Salazar Slytherin, one of the four founders of Hogwarts School of Witchcraft and Wizardry. His personal sigil was a serpent, and his ability to communicate with them was a defining characteristic. Because of this connection, Parseltongue became inextricably linked with Slytherin House and, more significantly, with his pure-blood supremacist ideology. The ability is hereditary and was passed down through Salazar Slytherin's bloodline, most notably to his last known descendants, the Gaunt family. The Gaunts prided themselves on their ancestry and their ability to speak Parseltongue, viewing it as a mark of their pure-blood superiority. The negative reputation of the ability was cemented by Lord Voldemort, the Heir of Slytherin, who used it openly as a symbol of his power and heritage. Consequently, any witch or wizard discovered to be a Parselmouth is met with immediate suspicion and fear, as it is almost universally considered a sign of a potential Dark Wizard. Harry Potter's public reveal of this ability during a Dueling Club meeting caused widespread panic and ostracism among his fellow students.

• Salazar Slytherin: The original Parselmouth from whom the ability was passed down to his descendants.
• The Gaunt family: Direct descendants of Slytherin, including Marvolo Gaunt, Morfin Gaunt, and Merope Gaunt. They spoke Parseltongue fluently amongst themselves.
• Tom Riddle (Lord Voldemort): As the last direct descendant of Salazar Slytherin, he inherited the ability and used it extensively to control serpents like the Basilisk and Nagini.
• Harry Potter: Harry was not a true Parselmouth by birth. He gained the ability when Lord Voldemort inadvertently made him a Horcrux, transferring a fragment of his soul—and thus some of his abilities—to Harry. He lost the ability permanently after the Horcrux inside him was destroyed during the Battle of Hogwarts.
• Ron Weasley (by imitation): In a moment of desperation during the Battle of Hogwarts, Ron was able to open the Chamber of Secrets by mimicking the Parseltongue sounds he had heard Harry make in his sleep. This was a single, functional imitation and not a true understanding or ability to speak the language.

The ability to speak Parseltongue is a crucial plot device throughout the series.

• Harry Potter and the Philosopher's Stone: Harry first uses the ability unknowingly at the zoo, freeing a boa constrictor.
• Harry Potter and the Chamber of Secrets: Harry's ability is central to the plot. He is ostracized after speaking to a serpent at the Dueling Club, leading many to believe he is the Heir of Slytherin. He later uses it to gain entrance to the Chamber of Secrets and understand the commands Tom Riddle gives to the Basilisk.
• Harry Potter and the Half-Blood Prince: Harry witnesses Morfin Gaunt and Marvolo Gaunt speaking Parseltongue in Albus Dumbledore's Pensieve, providing insight into Voldemort's ancestry.
• Harry Potter and the Deathly Hallows: Harry's ability allows him to understand Nagini when she is possessing the corpse of Bathilda Bagshot in Godric's Hollow. He and Ron Weasley also use it to open Salazar Slytherin's Locket, a Horcrux that would only respond to Parseltongue. Finally, Ron's imitation allows him and Hermione Granger to retrieve Basilisk fangs from the Chamber of Secrets to destroy other Horcruxes.

The term “Parselmouth” is likely an invention of J.K. Rowling. “Parsel” may be derived from archaic English or Old French words related to “speech” or “mouth” (e.g., Old French parler, “to speak”). The “-mouth” suffix clearly denotes one who speaks the language. Together, the term effectively means “one who has a serpent's mouth” or “one who speaks with a serpent's tongue.”

• In a 2007 web chat, J.K. Rowling confirmed that Harry Potter lost the ability to speak Parseltongue when the fragment of Voldemort's soul inside him was destroyed, and stated that Harry was “very glad to lose it.” (J.K. Rowling interview)
• Rowling also revealed that while Albus Dumbledore could understand Parseltongue, he could not speak it himself. (J.K. Rowling interview)
• According to Pottermore, the ancient Greek Dark Wizard Herpo the Foul, known for creating the first Basilisk, was also a Parselmouth. (Pottermore)
• For the film adaptations, a linguistics professor, Francis Nolan, was hired to construct a functional Parseltongue language. The actors, including Daniel Radcliffe, would then learn to speak the hissing lines created for the scenes. (film)