What does the picture on the back of an Alabama quarter represent?

The name Helen Keller is your answer.

An early-childhood illness left her both deaf and blind, but with the help of teacher Anne Sullivan she learned to read and write using the Braille alphabet, and to "hear" people speak by feeling their lips as they moved. She was the first deaf and blind person to earn a bachelor's degree, and became famous as an author and advocate for the physically impaired.

The raised dots above her name spell it again, but using the Braille alphabet.