What can you tell me about the word patois from The Awakening?

Patois — a French word that means native or local speech — is a form of a language differing generally from the accepted standard, as a provincial or local dialect. In Old French (spoken during the Middle Ages), patois meant incomprehensible speech or rude language.

Kate Chopin's The Awakening is set in 1890s Louisiana within the upper-class Creole society. Here, Robert is having a meal at Edna's house:

The dinner was of ordinary quality, except for the few delicacies which she had sent out to purchase. Old Celestine . . . hobbled in and out, taking a personal interest in everything; and she lingered occasionally to talk patois with Robert, whom she had known as a boy.