Quotations

In The Brief Wondrous Life of Oscar Wao by Junot Diaz, I am interested in the reason why the author would choose to eliminate quotation marks from the dialogue in this story. I can't recall if I have ever seen this before in a novel. Without the quotations, I feel somewhat disconnected from the scene, but not necessarily from the story. It seems as if the reader is being told what was said rather than feeling as if we are experiencing the dialogue as it happens. Perhaps the story is written this way to make us feel as if the storyteller is really speaking to the audience, in order to make us feel more connected to the narrator. There is definitely a sense that the narrator is almost like a friend, especially with the casual use of profanity. Does anyone have an idea of why the author omits quotation marks in this novel?