In a play, practically the entire story is carried out on the shoulders of the dialogue. Here, a writer who writes in many mediums needs to note that a dialogue in a short story or a novel tends to be quite different from the story told on stage or screen. Stage and screenplay dialogue has to fit the tone and the pacing of the entire work, and it must be written in a way that it can be uttered much more easily when compared to the dialogue in a story or a novel.

First and foremost, dialogue unveils characters. A playwright needs to have a good idea who his main players are and who they will become at the end of the play, inside and out. Characters in a play speak through their own vocabulary, accent, and life experiences.

Open the playscript of the famous play, Nora by Ibsen. See how in the beginning of the play, the husband plays the upper hand and Nora answers meekly. Then, observe how, at the end of the play, the dialogue has changed with the evolution of the plot and the characters.

As you are making your characters speak, make sure they are using their own words and not saying a pretty or clever idea the writer has put in their mouths. Even in plays written to underline some serious perspective or undertaking, like protesting social injustice, a player's dialogue should not consist of long tirades with excess verbiage.

To illustrate this point, let's look at an example. If you have a farmer Uncle John who is about to lose his farm and is only educated in the ways of the farm, he would not give a big speech with long words underlying the farm economy. Uncle John would not say in one breath, "Forming an equitable system of high-quality government is an imperative, for a good government must formulate farming to become profitable for whoever is disposed to be trained and is eager to exert bodily effort. The plight of the poor farmers is obvious or else most of the population will starve to death, and this capitalism will not save us from the farmer's predicament." Uncle John would be more likely to say, "Oh, my back! I'm bushed. Dangit! Too much...everything's too much. Hope it can be saved...the farm, I mean."

In the same vein, too many wisecrack answers in any one character's speech-just for getting laughs-can destroy the continuity of the story. The gags, even in a comedy script, must be compatible with the character, and the humor usually hides in the flow of the plot. In Shakespeare's All's Well That Ends Well the gags are uttered by the clown, fitting with his character.

Talking about Shakespeare's clown, a writer needs to pay attention to the speech of the minor characters, because their words are crucial in developing and advancing the play. Their dialogue, for creating drama and for pushing the plot forward, needs to be brief and to the point.

Observe how the parlor-maid advances the play in Pygmalion by George Bernard Shaw, in the beginning of Act V.

"THE PARLOR-MAID [at the door] Mr. Henry, mam, is downstairs with Colonel Pickering.

MRS. HIGGINS. Well, shew them up.

THE PARLOR-MAID. They're using the telephone, mam. Telephoning to the police, I think.

MRS. HIGGINS. What!

THE PARLOR-MAID [coming further in and lowering her voice] Mr. Henry's in a state, mam. I thought I'd better tell you."

To sum it up, the dialogue must fit in with the story of the play smoothly, must suit a character's personality, must be capable of being uttered effortlessly, and must be understood easily.