I'd like to know what the narrator means when he says at the beginning of F.Scott Fitzgerald's The Great Gatsby that "we've always been unusually communicative in a reserved way"?
In my younger and more vulnerable years my father gave me some advice that I've been turning over in my mind ever since.
“Whenever you feel like criticizing anyone,” he told me, “just remember that all the people in this world haven't had the advantages that you've had.”
He didn't say any more but we've always been unusually communicative in a reserved way and I understood that he meant a great deal more than that.
The Great Gatsby, by F. Scott Fitzgerald, is narrated by Nick Carraway. He introduces himself to the readers in the opening paragraphs of the novel, and how readers view everything and everyone in the story is based on their early perceptions of Nick.
Nick claims he is not like everyone else he is going to tell us about; he is from the Midwest and has a different set of standards and sensibilities about things than these outrageous, extravagant, and immoral people in New York. (What we learn later is that Gatsby, Tom, and Daisy are all also Midwesterners.) He also claims that he is one of the most honest people he knows, a rather immodest thing to say about oneself.
The quote you mention is part of what Nick's father taught him, reminding Nick that everyone has not had the same (presumably superior) upbringing as he has had. "He didn't say any more but we've always been unusually communicative in a reserved way and I understood that he meant a great deal more than that" seems to mean that the Carraways speak little but pack much meaning into what they do say. Perhaps an example of this is the last thing Nick says to Gatsby: "They're a rotten crowd. You're worth the whole damn bunch put together." These few words serve as a succinct condemnation of everyone else's bad behavior and his approval of Gatsby's unquenchable idealism.
Of course, Nick follows the comment by his father by saying he is one who tends to withhold judgments, a principle he most certainly does NOT adhere to throughout the novel. How the reader comes to view Nick probably determines how he comes to view Gatsby, as well.