Cousin (джен)

The boy grows more confident, smirk curling at his lips, “You don’t recognise me, cousin?” he sticks out his hand, “Hadrian Gaunt,” he introduces himself, “It’s always nice to find long-lost family, am I right?”
It’s only then that Tom realises the whole common room is staring at them, and it takes him too long to realise the reason why is because the whole conversation between the two of them hadn’t been in English.
It had been in Parseltongue.