What does scout notice about Calpurnia's way of speaking at church

What do the children notice about Calpurnia's behaivor in her church community? Scout and Dill do indeed hear Calpurnia move from the standard (Southern) dialect that they're used to hearing her speak to a more strongly marked black dialect when they accompany her to church in Harper Lee's novel To Kill a Mockingbird.

Calpurnia speaks in the same dialect as the others in the church, but at home Calpurnia will speak proper English. Scout learns that Calpurnia acts different compared to when she’s at home with the Finchs.