In To Kill a Mockingbird by Harper Lee, what is the purpose of Lula's interaction with Calpurnia when she takes Scout and Jem to church with her?
Lula inadvertently gives Scout and Jem their first real look at the black community outside of their relationship with their beloved Calpurnia. Calpurnia is the epitome of a lady when she is at the Finch home; her manners and spoken words are as refined as any white person's, and she insists on that same behavior from Jem and Scout. When Lula approaches Cal and the children, she is clearly in a confrontational frame of mind, saying, "I wants to know why you bringin' white chillun' to nigger church." Cal doesn't back down, stating, as Lula approaches them, "Stop right there, nigger." As the children are discussing the incident with Cal later that day, Scout observes:
That Calpurnia lead a modest double life never dawned on me. The idea that she had a separate existence outside of our household was a novel one, to say nothing of her having command of two languages.
Jem and Scout ask Cal why she had addressed Lula in that type of dialect, since "you know better", in Jem's words. Cal explains to the kids that, "It's not necessary to tell all you know. . . .folks don't like to have someone around knowin' more than they do. It aggravates 'em."