Ahhh yes...
Been wanting to do this one for a while.
Of course he's in gryffindor, I mean really!
And how does he do spells you ask if he can't say incantations?
Well it does state that some African wizards do not use wands, and that there are some wizards who merely has to think of their spells to get it done. Being a monster, we can assume he has his own special abilities with magic, and perhaps that as well.
Swish and flick, Monster Kid! SWISH AND FLICK!