How does calpurnia learn how to speak proper?

Answer 1

She says she can't quite remember; she says it was a book given her by one of Atticus' ancestors.

Answer 2

Calpurnia learns to speak properly through education and exposure to correct language usage from various sources, such as her interactions with the Finch family and her attendance at church. She also likely made a conscious effort to improve her speech to be respected in a predominantly white society that valued standard English. Over time, her language skills and fluency would have improved through practice and consistent application of correct grammar and vocabulary.