I was a bank teller in high school/university and I was basically a glorified cashier. I've always had trouble with the "H"in the "How are you today?" but worked on a few scripts to get around this. I was so nervous before my first shift, but I got through it and kept at it. I was never fluent, but the customers didn't really care and were mostly patient - I was providing a service to them/helping them out after all. Successes bred successes - now I talk/fight/negotiate with government taxation auditors regularly and couldn't care less if I stutter.