It's not his voice that she hears - she doesn't hear it, she's above the water when he calls - but she notices the hair and then remembers that she knows the person attached to it, and then she's swimming closer to the bank for a better look. The closer she gets, the clearer it is that she looks a little different in ways that light and water can't account for with blue-black eyes and skin like mother of pearl and a tail the same, propelling her on and still moving, restlessly, when she comes up alongside.

(There's what looks sort of like a distorted bitemark on the back of aforementioned tail, where it'd be high on her thigh if she had thighs right now, but it's hard to get a proper look and it's probably healing, anyway.)

"What are you doing out at this hour?" And what are you, his mother? Ilde is not actually in a position to criticize anyone else's judgement, bossy naiad tone aside.