Zora Neale Hurston uses dialect to help her characters appear to be real people with actual cultural backgrounds.
A character's dialect is a large part of who they are as a person. It can show where they come from and who they aspire to be. When Janie speaks in the deep southern dialect of her community, it shows the reader where she comes from. It helps place her in the world of the story.
Many authors opt to use "standard" English, which is what is taught in school and tends to reflect the speech of a generic white, upper-class American. In Their Eyes Were Watching God, the dialect makes it more difficult for some readers to easily skim the text at first. They have to read more deeply into what the characters are saying to understand their intent. It makes readers have to connect more deeply to the characters as they work to understand them.
For example, early in the book, a character says,
Humph! Y’all let her worry yuh. You ain’t like me. Ah ain’t got her to study ’bout. If she...
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