to kill a mockingbird

When Calpunia takes the children to church, a black woman named Lula tries to tell her that white children don't belong at the church. However, Calpurnia points out that it's the same God, and the rest of the congregation welcomes the newcomers. Scout is surprised to hear Calpurnia speak in the same black dialect as the others, because at home, Calpurnia always speaks proper English. Scout then asks her why they don't have hymnbooks at her church, and Calpurnia explains that only a few people at the church can read. Scout also learns that Calpurnia used to work at the Landing for Miss Maudie's aunt, Miss Buford, who taught her to read. Jem asks Calpurnia why she doesn't speak with proper grammar around black people, and Calpurnia explains that it would be out of place, and that she would look pretentious. The others don't want to learn to speak the "right" way, she says, so she speaks their language.

This definitely can be attributed to real life. People act differently around their co-workers than they do their family..... and they act differently around their families than their friends.