"Oh, definitely!" Katara said, grinning. "I'd even like something like that."

[She walked along with him, then her grin started to fade a little as she found it just as hard to breathe. Her face reflected exactly hwo anxious it made her too: she look wordlessly at Billy in alarm, and saw that he was in pain too. She was starting to freak out, then made a beeline for going underwater.]

Billy! [She said, and was startled to see her words were still understandable, underwater...AND that she could breathe.] What's happening?