Annie Sullivan achieves amazing things in her education of Helen Keller and The Miracle Worker reveals many of the sacrifices required from everyone concerned in Helen's welfare. Helen's half-brother James has, perhaps involuntarily, made sacrifices as, apart from the fact that Kate Keller is Captain Keller's second wife and not James' mother, any time his father may have is, in James' mind, spent on managing Helen. James even notes how Annie seems to have won his father's respect and yet he cannot.
Captain Keller makes various sacrifices, mainly compromises at first, in the pursuit of his dream of contentment for his wife and daughter. Despite being on the verge of firing the insubordinate Annie, she eventually makes him understand that giving in to Helen is not the way to show her their love. "Even learning 'no' has been at a cost. Of much trouble and pain. Don’t undo it" (Act III) is Annie's plea to him. Unfortunately, his resolve does not last long and he almost gives in to Helen on her first evening back in the main house as the "guest of honor."(Act III)
Helen's mother, Kate, so desperate to help her daughter, knows that she has allowed Helen to rule their lives and that things have got to change. It is an enormous sacrifice for her to let Annie stay with Helen in the summerhouse for two weeks and to have no contact but she does it. However, as with Captain Keller, on Helen's first evening back home, she allows Helen to get the better of her and, only for Annie's intervention, can a return to Helen's former ways be avoided.
Annie herself has made many sacrifices in helping Helen; she has been mocked by James, although not maliciously; she has been questioned, doubted and berated by Captain Keller, pleaded with by Kate and completely abused by Helen and yet she has persevered. Momentarily, it becomes evident that Annie has changed Helen's and the whole family's lives as she grasps the concept of words and her journey towards communication begins.