Calpurnia learned to read from The Bible and a book Scout's grandfather gave her.
The Finch family housekeeper Calpurnia is one of very few African-Americans in Maycomb who knows how to read. She was taught how when she grew up on Finch’s Landing, Scout’s family’s land. Her employer Miss Buford taught her how to read using the Bible, and then she taught her son.
Scout and Jem had no idea that so few African-Americans could read until they went to church with Cal one day.
“Can’t but about four folks in First Purchase read… I’m one of ‘em.”
“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. 12)
Calpurnia, who is older that Atticus, tells Scout that she made her son learn to read even though there was no school for him to go to because of his skin color. She taught him to read the same way that she learned to read—from the Bible.
“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. 12)
Calpurnia’s situation demonstrates the inequality of racism and segregation. There were no schools for African-Americans. The church was full of people who were illiterate, and they had to sing their hymns through a method calling lining, where the person who could read would read the hymns and then everyone would repeat them. When Scout and Jem go to church with Calpurnia, they get a glimpse of the way the other half lives in Maycomb.
The gift of the book for teaching reading demonstrates that Atticus is not the only Finch who cares about others. It seems to show that Scout's grandfather had similar views of human nature, because he tried to help Calpurnia learn to read. She passed on what she learned to her son, creating two generations of educated African-Americans.