Tris thought there might be something wrong with him.
Otherwise, it was hard to explain why he would greet a potentially deadly Magical Serpent.
But the moment he called out "Nagini," there was no taking it back.
The great snake, who had been about to slip into the water and swim away, stopped and turned back. Most of her body remained submerged, but she raised her head and let out a series of rustling hisses.
To Tris, those sounds became intelligible words: "You recognize me."
It really was Nagini.
Tris felt as though his head might burst with all the questions crowding into it.
First, why was Nagini here? Second, why could he understand Parseltongue?
He had plenty of guesses about the former. Or perhaps he could simply ask the Magical Serpent Nagini before him.
But the latter left Tris utterly baffled.
He was certain he had never understood Parseltongue before! There were plenty of snakes in Britain, and he had seen no shortage of them at the Burrow. He had never seen one four or five meters long, but snakes two or three meters long were fairly common.
Yet he had never heard a snake speak.
Surely snakes didn't have to reach a certain length before they could talk?
But Parseltongue seemed to be an innate ability. The only known exception was Dumbledore, who could understand it but couldn't speak it himself.
Besides, at least in the limited material Tris had gathered over the past few years, he had never heard of anyone learning Parseltongue.
"Why aren't you speaking?" Seeing Tris standing there in a daze, the Magical Serpent Nagini asked another question.
"Ah... I'm a little... well, nervous." Tris swallowed. "I didn't expect you to actually answer me. Or rather... I didn't expect it to really be you."