She makes up her mind to teach him the rest explicitly when they've finished the mass.

And, after its runtime, they are done. "There's a bunch of those signs. You want to know the rest? They're really handy. Also, you can use them as rude gestures if you want to insult someone who's singing, although I don't recommend doing that to anyone sensitive or humorless. Or anyone who'd take you seriously. Serah sharped Moriah so much one time that poor Moriah wound up transposed, a full step down."