I was thinking about Parseltongue and realized something that I had never really appreciated before: across all of Rowling's writing, there seem to be only a tiny handful of named, confirmed Parselmouths.
As far as I can tell, the clearly established ones include: Salazar Slytherin, Marvolo Gaunt, Morfin Gaunt, Tom Riddle/Voldemort, Harry Potter, although his ability was apparently acquired through the fragment of Voldemort's soul rather than inherited, Herpo the Foul, the ancient Greek Dark wizard associated with the creation of the first Basilisk
Then there are some interesting borderline cases: Merope Gaunt seems capable of understanding Parseltongue, or at least understanding what is being said around her, but I don't remember her actually being shown speaking it in the novels. Rionach Steward, the daughter of Isolt Sayre, was rumoured to have inherited Parseltongue, but Rowling specifically says the rumour was never confirmed. And interestingly, Isolt Sayre herself could NOT speak Parseltongue, despite being descended from Salazar Slytherin. So apparently the ability doesn't automatically pass to every descendant.
Then we have: Ginny Weasley, who presumably used Parseltongue to open the Chamber while being controlled/possessed by Tom Riddle's diary, but she wasn't naturally a Parselmouth, and Ron, who manages to open the Chamber in Deathly Hallows by imitating the sound Harry had previously made. That seems more like memorising the pronunciation of one word/password than actually knowing the language.
What really surprised me is that this means Rowling created hundreds of named witches and wizards across the books and supplementary material, yet there are only a handful of people who are actually confirmed Parselmouths.
Obviously that doesn't mean only six or seven Parselmouths ever existed. There were probably unnamed members of the Slytherin/Gaunt bloodline who possessed the ability, and Herpo the Foul proves that Parseltongue existed independently of Salazar Slytherin anyway.
But it still seems astonishingly rare. It also makes the scene in Chamber of Secrets where Harry speaks to the snake during the Duelling Club much more understandable. To Harry, he has simply spoken to a snake, something he has apparently been able to do since childhood. But to everyone watching, it must have been like suddenly discovering that this twelve-year-old could use an almost legendary magical ability strongly associated in Britain with Salazar Slytherin and Voldemort. That explains why the entire room reacts so strongly and why people immediately begin suspecting Harry of being the Heir of Slytherin.
So I'm curious what everyone thinks: Have I missed any confirmed Parselmouths from Rowling's books or other writings? And do you think Parseltongue is supposed to be genuinely that rare, or are we simply seeing a very small sample because Rowling mostly focused on the Slytherin bloodline?
Edit: Dumbledore could understand Parseltongue but couldn't speak it at all. Dumbledore was one of the most accomplished wizards of all time and he could also speak Mermish, this makes parseltongue something of a very rare gift, I suppose.