The film focuses on the communication between Annie and Helen Keller, and the development of Helen's ability to learn and communicate. The story is about overcoming obstacles and finding a way to connect with a deaf-blind child.
While the film touches upon the concept of sign language, it does not focus on its history or the person who invented it. The deaf alphabet, also known as fingerspelling, is a visual representation of the letters of the alphabet, and it's used to spell words and names.
It's important to note that fingerspelling was not invented by one single person, but rather developed over time by deaf communities around the world.