Some prime examples is when Marguerite's mother chats with Sister Flowers and uses the wrong verb "is" instead of "are." Marguerite is pretty embarrased for her and her mother's sake and in my opinion it shows how much Marguerite would like her mother to be more like Sister Flowers. She even goes as far as to say that she "hated her [mother] for showing her ignorance." This helped me to understand how highly Marguerite regarded Sister Flowers and how much Marguerite would like to be like Sister Flowers.
The reader can also pick up on the difference of grammar between Sister Flowers and Marguerite's mother throught their dialogue between each other and with Marguerite. It's easy to identify Marguerite's mother with a more southern accent as the author has intended by the use of slang. And the protagonist has clearly picked out deficiency in her mother's sentence structure and choice of words. Sister Flowers uses no such slang and her words are properly used.
Marguerite has a veneration for Sister Flowers for a number of reasons: the way she dresses, the way she carries herself, her body shape and even the richness of her skin. The way Sister Flowers speaks and uses her grammar is also another feature that Marguerite