[ A complement would fit neatly here — Yours is more than serviceable — but if its absence is notable, so may be the fact he does continue conversing with her in it. ]

And versatile. [ Versabilis— changeable, shifting, the whipping of a flag in the cross-wind. ]

Not everyone speaks it with nuance, of course, [ here's looking at you, un-expellable Altus kids, ] but I can imagine the usefulness of that knowledge, considering your enemy.

[ He's hardly the only young mage to have taken to it like a secret code. ]