User blog comment:Yugimuto1/Spells incantation/@comment-1613839-20130411132055

It's as Peri said. We try to stick to canon and so if there is no incantation we either refer to it with the spell name, make up an incantation, or insist that it's a non-verbal only spell (if it's 5th Year or above) so there IS no verbal incantation.