"Tristran," she gulps audibly at the change in his expression, snagging his fingers back between hers. "Tristran, you can't do that. You have to be cheerfully optimistic at me or else I am going to - I am going to panic and I am going to listen to that very convincing little voice in the back of my head that is telling me that your parents are going to hate me and then you are going to hate me for making your parents hate me and then I am going to wish that I was a lump of rock because, at the very least, rocks cannot talk."

Actually, it would be a lot easier if -

"Can we tell them that I cannot talk?"