Gwen continued scribbling down notes.
She wasn't quite sure what Charms were. All Gwen knew about them was that they were spells one could use to alter and change something about the intended object or person which could be used with a verbal or non-verbal incantation.
She knew this because her father had made a point of lecturing her all summer long. A few days ago he was still going on about the differences between trolls and giants when she'd stepped on to the Hogwarts Express at King's Cross Station.

Gwen decided to give Professor Schirmer's question a shot and raised her hand, a little nervous.
"Professor, I know very little about Charms, but I'm quite sure that the incantations can both verbal and non-verbal."