Parselmouth

"No. Sorry," Harry said, tone apologetic. "Look, did you see a tall, dark haired man with eyes like mine walk in a couple of minutes ago."

"Yes. He hissed, and the sink opened up for him. Then he disappeared," Myrtle said. She lowered her voice. "He went down into the Chamber of Secrets."

Harry frowned in thought. "Thanks," he said, then went up to the sink, and hissed, "Open up."

He stood back as the sink opened up. He looked down the dark, forbidding chute. Last time he'd been down there, he'd been with Ron and Lockhart. He'd nearly died. Ginny had nearly died. She'd been hurt – something which bothered him in a less abstract fashion than it once had. He gulped. There wasn't a basilisk down there anymore. And if something went wrong, his uncle could protect him – maybe the reason he'd gone down there in the first place was because he knew about the Chamber, and since he taught the Founders, he probably did. He smiled slightly and remembered something a character he liked on muggle television called 'The Doctor' liked to say.

"Allons-y!"

He leapt down the chute.

—-Chapter 5, Understanding