User blog comment:MilitaryBrat/Lord Voldemort vs Darth Vader/@comment-181289-20111217025951/@comment-4248317-20111218095711

@Swg66 I know it can be cast nonverbally in the movies at least, and J. K. Rowling personally approves everything that happens in the movies.

I even asked my mom, who is also a die-hard Potter fan, and she says avada kadavra CAN be cast nonverbally, if the wizard casting it is powerful enough, like Voldemort.