In chapter 12, what new things does Scout learn at the First Purchase Church about how the black people live?

One of the first things Scout learns is that prejudice is a two-way street.  When the children and Calpurnia encounter a disgruntled church member named Lula who questions Calpurnia about bringing white children to their church and says that they don't belong there.  Scout also sees how Lula's prejudice upsets Calpurnia.  Calpurnia's church is much simpler than the church that the Finch's attend and Scout discovers "linin'" which is when one person sings a line of the hymn and the rest of the congregation repeats it.  They do this because most of them can't read even if they could afford hymnals.  Scout finds out that Calpurnia speaks differently at church among the other blacks than she does when she's with the Finch family explaining to Scout that to speak in her perfect English to friends (the way she speaks at the Finch household) would be considered "uppity".  Scout also learns more about Tom Robinson and the case that Atticus is taking on.  She finds out that Helen, Tom's wife, has no income now that Tom's in jail and that Rev. Sykes will "sweat" the money out of the congregation keeping them in church until enough money has been raised by the congregation. After church Scout finds out that Calpurnia was taught to read by Miss Maudie's aunt, Miss Buford, and that's why she speaks so well.