In Vanity Fair, there are masters of one language, masters of many languages, and those whose lack of education puts them perilously close to illiteracy. Individuals who are able to find many different modes and styles of communicating, and can make themselves understood by as wide a variety of social, political, and economic ranks as possible will have an edge. Again, Thackeray's main protagonist shines in her ability to express herself in an almost unlimited number of ways.
It is important for a character not simply to be able to communicate in different styles, but to be able to interpret the looks, gestures, allusions, and jokes of others in the correct fashion. By stressing this skill, the novel allies itself with its readers, who are its interpreters.
The novel tries out different ways to use letters. There are letters of revelation (like Miss Pinkerton's bio of Becky for Mrs. Bute), letters of characterization (for example, Sir Pitt's note to Becky about meeting him), letters used to con their recipients (such as the letters from "Rawdon" that Becky sends to Miss Crawley), and letters used as narration for the novel (see Becky's long letter to Amelia about Queen's Crawley). So important is written communication that the resolution of the plot hinges on a note from George to Becky. Ultimately the novel favors writing over performing in its ranking of artistic or creative pursuits.