Kincaid writes with some of the most precise English we've ever encountered here in the Shmoop-iverse.
Sometimes, this hyper-precision is used as an effect, like her explanation that the Mill Reef Club doesn't like "Antiguans (black people) at all" (2.3). We see parentheses pop up a lot throughout the book, sometimes to reveal the narrator's inner feelings, and other times to thoroughly explain her ideas, like in the example above.
As the author, Kincaid has a tendency to stretch paragraphs out for ages. Oddly, though, these paragraphs rarely become confusing because Kincaid writes in such proper English. We can't help but see a similarity between this stylistic choice and the narrator's anger at being forced to speak English: In Kincaid's precision, the narrator proves that she has mastered the "language of the criminal" (2.3) that she resents so much.
All in all, Kincaid's style is completely unique—at times super proper, at others casual and personal. The only things that never change are her biting sense of humor and absolute fearlessness.