I was chatting with one of my players today, and he asked me a question about spellcasting that actually piqued my interest.  After a recent tussle in the middle of a apartment complex, he decided that he wanted to make a rote to either silence his gun specifically or silence the area their fight breaks out in.  His question was involving the act of spellcasting and whether or not silencing a zone would negate the ability to cast spells entirely.  I didn't quite know how to answer, as Dresden has mentioned several times throughout the books that the verbal component is near vital (as is the requirement of using a different language during the casting) in order to erect the mental barrier that keeps the magic's energies from short circuiting the casters brain.

If a caster has no ability to speak (because of his silenced zone), should they be able to cast?  I was going to allow them to do so, as all but one of my players are running as a spellcaster in one form or another, but with a -1 to their Discipline while standing inside the border of his spell.

Thoughts/Comments/Ideas?