The miracle that occurs at the end of The Miracle Worker is that Helen Keller learns to communicate with words. The audience, therefore, has the sense that this is a turning point in her life and that, although her story is far from over, it will be quite different from now on.
When Helen manages to spell out the word water, the Keller family come running from the house. Helen touches her mother's skirt, and Annie spells out the word mother for her. Then she spells papa for her father. The word Helen particularly wants, however, is teacher, which is, for her, as important a relationship as any family member as far as she is concerned.
The final image of the play has the family retreat from the two figures of Helen and Annie, as Annie spells into Helen's hand, "I love Helen. Forever and ever." Both words and action reinforce the idea that the play is about Annie, the miracle worker herself, and Helen. Her family and the rest of the world are all subordinated to her teacher.
Throughout the play, Helen's view of the world has been different from anyone else's, and this has been the source of most of the conflict. Only Annie has shown real understanding of Helen's world. Now, in these two figures and Annie's message of love, the audience is given a glimpse of how the world appears to Helen Keller.