There are only two "voices" (characters) in Jamaica Kincaid's "Girl": a mother and her daughter. The story is told in a very loose, kind of stream-of-consciousness voice, and every line in the piece is spoken by the mother--except for two.
We know which lines are spoken by the daughter because they are set in italics, and it is clear that her mother is much more interested in talking than in listening. The entire piece is full of advice (sometimes in the form of condemnation) about how a woman should conduct herself as a wife and a female of good character. The advice is blunt and practical, but it presumes that the daughter is not a good girl. (She may not be, but how would we know?)
The story is all one sentence, with each piece of advice separated from the others by a semi-colon. After ten different pieces of advice, the mother says this:
...don't sing benna in Sunday school; you mustn't speak to wharf–rat boys, not even to give directions; don't eat fruits on the street—flies will follow you; but I don't sing benna on Sundays at all and never in Sunday school; this is how to sew on a button; this is how to make a button–hole for the button you have just sewed on; this is how to hem a dress when you see the hem coming down and so to prevent yourself from looking like the slut I know you are so bent on becoming....
As you can see, the mother barely takes a breath while her daughter speaks--and then she just keeps on going. She does not listen and, even worse, she does not care what her daughter has to say. The mother clearly dominates this one-sided conversation (lecture).