"You understand him, I'm sure, Harry?" said Dumbledore quietly.
"Yes, of course," said Harry, slightly nonplussed. "Why can't Ogden--?"
But as his eyes found the dead snake on the door again, he suddenly understood.
"He's speaking Parseltongue?"
"Very good," said Dumbledore, nodding and smiling. (10.65-69)
Parseltongue is the language that snakes speak. One of the original founders of Hogwarts, Salazar Slytherin, was a powerful and power-hungry wizard who could speak Parseltongue. He handpicked students for Slytherin house way back in the day, favoring those who could speak to snakes. Both Voldemort and Harry are Parselmouths.
The post owls arrived, swooping down through rain-flecked windows, scattering everyone with droplets of water. Most people were receiving more post than usual; anxious parents were keen to hear from their children and to reassure them, in turn, that all was well at home. (11.8)
There is no e-mail, no TV, no text messaging, and no Tweeting going on at Hogwarts. The students communicate with the outside world via owls, and they hear about what is going on outside castle walls via the Daily Prophet, a newspaper.
Hermione pressed her lips together, looking angry and disapproving, but was distracted by a third owl landing in front of her carrying that day's copy of the Daily Prophet. She unfolded it hastily and scanned the front page. (11.25)
Hermione is very aware of what is going on in the world. She takes it upon herself to be informed. Everyone at Hogwarts is pretty isolated from the outside world, and the Daily Prophet helps them stay connected. As the wizards and witches in Harry's year get closer and closer to graduation and to the knowledge that they will be released into the outside world, they begin to understand that their education is teaching them how to survive in the real world, how to use their magic to the best of their abilities.
Harry stepped forward and bowed low to the hippogriff without breaking eye contact or blinking. After a few seconds, Buckbeak sank into a bow too. (11.79)
Part of being a good wizard has to do with knowing how to communicate with creatures of all different kinds. This takes great awareness, compassion, and a willingness to get to know a perspective different from one's own. Harry seems to be good at this.
"Yes, I certainly do know that you have seen and done much since leaving us," he said quietly. "Rumors of your doings have reached your old school, Tom. I should be sorry to believe half of them." (20.166)
Rumors and gossip are a huge part of how information gets passed around in the world of Harry Potter. We almost think that rumors and gossip play a bigger role in Harry's world than it does in our own, but you might disagree with us. What do you think?
Voldemort's expression remained impassive as he said, "Greatness inspires envy, envy engenders spite, spite spawns lies. You must know this, Dumbledore." (20.167)
Lies and deception form the glue between the obstacles that stand in Harry and Dumbledore's way. One must often sift through such lies when one communicates with someone in the Wizarding community in order to find out what truth is at the heart of the matter. Voldemort seems to know this and is able to manipulate communication well.
"I need you to become the place you became for Draco Malfoy…" (21.102)
Harry tries to activate the Room of Requirement by using his thoughts only. Throughout Harry Potter and the Half-Blood Prince, the young witches and wizards begin to learn how to conduct magic silently, using their mind alone. Here, we see Harry struggle with this complex kind of magic.
"It is Voldemort's fault that you were able to see into his thoughts, his ambitions, that you even understood the snakelike language in which he gives orders, and yet, Harry, despite your privileged insight into Voldemort's world (which, incidentally, is a gift any Death Eater would kill to have), you have never been seduced by the Dark Arts, never, even for a second, shown the slightest desire to become one of Voldemort's followers!" (23.152)
It is Voldemort who gives Harry access into his Dark mind and to his Dark thoughts. Harry and Voldemort share an intense connection precisely because Voldemort built that connection. Harry communicates with Voldemort in a way that no other person is able to.
As they flew over the dark, twisting lane down which they had walked earlier, Harry heard, over the whistling of the night air in his ears, Dumbledore muttering in some strange language again. He thought he understood why as he felt his broom shudder when they flew over the boundary wall into the grounds: Dumbledore was undoing the enchantments he himself had set around the castle so they could enter at speed. (27.45)
Language is used to not only communicate feelings, wants, and needs in Harry Potter, but it is also used to perform magic. It is a means of survival.
"Tell me, how have you been communicating with Rosmerta? I thought we had all methods of communication in and out of the school monitored."
"Enchanted coins," said Malfoy, as though he was compelled to keep talking, though his wand hand was shaking badly.
"Isn't that the secret method of communication the group that called themselves Dumbledore's Army used last year?"(27.187-189)
Malfoy is able to penetrate Hogwarts with Dark Magic by manipulating means of communication.
Harry wondered where Dumbledore had learned Mermish. There was so much he had never asked him, so much he should have said…. (30.123)
A huge chunk of Dumbledore's wisdom has to do with his ability to communicate with and, therefore, to understand so many different kinds of wizards, witches, and magical creatures. He is a true leader because, rather than isolate himself from the Wizarding community, he has sought to educate himself on the diversity within it. He values the various cultures, beliefs, and languages that exist within this community.