[He keeps on looking proud, but also surprised, as he goes on.]

She did, huh? Wow, Korra must be taking to airbending really well if she's able to teach a little! [It's a far cry from the first times he met Korra, when she wasn't even able to airbend.] I'm proud of her, and of you.

You had an even better handle on it than I thought. How about while we wait for the others, we'll do some breathing warm-ups.