Jem says that Scout has been reading almost since she was born. Reading is a theme throughout the book. It is about education. The fact that Calpurnia can read, when most of her church cannot, is indicative of how she is much more educated than most people of her color. She was taught by Miss Maudie’s aunt, not in a school.
When Scout asks Calpurnia why they don’t have hymn books in her church, she responds that it wouldn’t do any good since they can’t read.
“Can’t read?” I asked. “All those folks?”
“That’s right,” Calpurnia nodded. “Can’t but about four folks in First Purchase read… I’m one of ‘em.” (ch 13)
Scout is stunned.
“Where’d you go to school, Cal?” asked Jem.
“Nowhere. Let’s see now, who taught me my letters? It was Miss Maudie Atkinson’s aunt, old Miss Buford—” (ch 13)
Scout is also surprised when she learns that Cal taught her son how to read, and how.
“Did you teach him out of a primer, like us?” I asked.
“No, I made him get a page of the Bible every day, and there was a book Miss
Buford taught me out of—bet you don’t know where I got it,” she said.
We didn’t know.
Calpurnia said, “Your Granddaddy Finch gave it to me.” (ch 13)
When Scout learns how Cal learned to read, it makes her realize two things. First, not all children have the opportunity to go to school. Second, Calpurnia has a deep history with their family. She came from Finch’s Landing. It is another example of class and racial differences Scout is learning about as she slowly grows up.