I'd like to introduce a character that stutters into a screenplay and wanted to know if there's any hard and fast rule in which to do that. I had a look at the screenplay of the only film I could remember with a stutterer, A Fish Called Wanda, and found Cleese writing it as it sounded - "Nnnno he had to ggggo ttttto the bbbbank". I wondered though if us mere mortals are expected to write it into the character description or parenthetical.