Haroun and the Sea of Stories involves a strong component of fantasy.  The events that happen to Haroun are quite magical, and require the author to wield language in a way that allows the reader to imagine the impossible.  Story and meaning are created by the author through the use of imaginative language in order to create the magical world that the novel inhabits.  This, itself, is the power of stories.  With the use of imaginative language an author can bring meaning to something that before that moment did not exist at all.  The creation of the magical and impossible through words is what rends the language use so powerful.