Who is El Mudo from A Loss for Words: The Story of Deafness in a Family and what is their importance?

El Mudo (Spanish for "The Deaf One) is a young man Lou Ann interprets for in the court system. She points to his case as more evidence that the justice system is poorly equipped to handle the deaf. El Mudo was duped by his friends into driving a getaway car during a robbery. Though El Mudo understands little, he is given several years in prison.