What your coworker who stutters craves is to be treated in every sense like communication with her is not a problem. The onus is mainly on HER to become as fluent as possible, and to become as OK with stuttering as possible. As far as how to communicate with her: maintain friendly eye contact, be as non-reactive to the speech blocks as you can, and by all means, help her finish words if she is struggling and you feel compelled to help (although it does hurt my pride when others do this, I recognize they are just trying to help and its my issue to get over). Treat her with respect and acceptance and youll be giving what her heart yearns for in human interaction