When he goes to Alabama in Chapter 4, the narrator not only quotes but also describes the dialect of the Black people he encounters there:
Only one thing about them awoke a feeling of interest; that was their dialect. I had read some Negro dialect and heard snatches of it on my journey down from Washington; but here I heard it in all of its fullness and freedom. I was particularly struck by the way in which it was punctuated by such exclamatory phrases as “Lawd a musy!” “G’wan man!” “Bless ma soul!” “Look heah chile!” These people talked and laughed without restraint.
The narrator has described the people themselves with a certain amount of contempt. Having grown up in Connecticut, where he received a middle-class education alongside white children, he is struck by how poverty and segregation have affected people of color in the South. Some of his dislike seems to come from internalized racism and the idea that white culture (in which he has partially been raised) is superior to Black culture. Nonetheless, the dialect of the Black Southerners produces a "feeling of interest" in him. He is especially impressed by the way full body laughter is incorporated into their speech. This is the same kind of full-body expression the narrator has tried to achieve in his music. He is frustrated that people always called him a child prodigy, emphasizing his technical skill instead of noticing that he is a good musician because he plays with passion. Whereas white Northern culture prizes restraint, structure, and displays of talent and learning in speech and music, this moment is when the narrator first encounters a culture that prizes free, embodied, emotional expression more than technical correctness.
More recent research by linguists demonstrates that African American Vernacular English (AAVE) in fact has its own internal grammar rules and that there are indeed correct and incorrect ways of speaking it. The narrator fails to recognize the legitimacy of Black Southern speech as its own formal language, but his appreciation for its connection to emotional expression is key to his later interest in the possibilities of ragtime.
