Have you ever told them that you stutter? Be upfront about it, if they make fun of you fuck them, we're only alive for a short time, don't be worried about ignorant dickheads making fun of something they know nothing about. I know its really hard not to give a shit when you have your job involved but worrying about what people think of you isn't healthy. Walk in with your head held high and own that stutter, it defines you, thats what makes you unique in your job. Are you gonna let some prick get the better of your just because you stutter? No. stay strong, I hope your job gets better.