The study examines the facets of Arab fiction writers` use of colloquial(``Ammiyah) as vehicle of conveying the dialogues between characters. Since the Arabs continue to speak ``Ammiyah, while write down in literary Arabic(Fusha), Arab writers used have troubles in representing the reality through their language. Chapter I introduces the ``Ammiyah problem in Arabic literature and defines the themes of discussion. Chapter II is specified to summarizing the history of using ``Ammiyah in the Arabic novel. It also points out that ``Ammiyah may have efficiency in constructing characters. Chapter III examines the function of the dialogue in the novel in general and surveys the stylistic features of the two levels of Arabic. Chapter IV analyzes the aspects of ``Ammiyah dialogue as shown in the several works of Arabic novel and short stories. The essay points out that the writers employed ``Ammiyah in the dialogues for various reasons. With ``Ammiyah they gained stylistic diversity as well as the lifelike and vivid effects that cannot be achieved in Fusha. The essay concludes that ``Ammiyah will open a new horizon in the coming period, especially with the expansion of literary innovation and the advent of experimental fiction, because it may endow the writers with more flexible tool for expression.