Just like in movies, good fiction needs dialogue to engage readers and infuse its story with drama. There's more to the purpose of dialogue, though, than just giving the main players words to say. Through characterization and plot development, dialogue is ultimately a source of critical information in helping readers understand the story.
The way a character speaks can provide a lot of information. Because the characters each have distinctive voices, realistic, well-written dialogue will introduce readers to them in ways that show their most important attributes. For example, a character who is an aspiring filmmaker might habitually talk in movie references, while an angry teenager might use short, clipped speech and slang in his interactions with others. Good dialogue gives subtle hints to readers about the characters' personalities, backgrounds and interests that will continue to develop throughout the story.
Dialogue is also critical to plot advancement. Conversations between characters often provide critical moments of conflict or turning points, as what they talk about often affects the decisions they make later on. In F. Scott Fitzgerald's "The Great Gatsby," for example, narrator Nick Caraway keeps secrets for Daisy and Gatsby, hiding his knowledge of their past and present affairs. The scenes of dialogue where they share this information with him drive the story toward the climactic argument between Gatsby, Daisy and her husband, Tom, that reveals the affair. Dialogue increases the tension between characters, creating suspense about the story's possible outcomes.
Shape of Things to Come
Dialogue is also a tool of foreshadowing, the presentation of details that look forward to future events in the story. Conversations between characters can include dialogue that may be overlooked on the first reading of a work, but takes on greater significance later. Stephen King uses this technique in "The Green Mile" when Paul Edgcombe, a death row prison guard, muses that his colleague, Percy Wetmore, lacks compassion and common sense, and that eventually, he'll hurt somebody. This line foreshadows Percy's sabotage of the execution he officiates later in the novel. Foreshadowing in dialogue gives readers subtle hints about characters and events while paving the way for future action.
Dialogue is one way readers learn about the setting and conflict in a story's exposition. While good fiction doesn't include lengthy explanatory dialogue, short, realistic lines with key details can teach readers the rules of the story's world. In Shirley Jackson's "The Lottery," dialogue is a key tool for telling readers about the small town's peculiar lottery ritual. For example, the lottery's supervisor explains the rules of the drawing, while an old man complains about how the ritual has changed over the years. Reading dialogue can provide readers with information that is more meaningful coming from the characters themselves.