Verbal irony occurs when a character or narrator says one thing but means the opposite. Shakespeare's work is rife with verbal irony: in Act III of "Romeo & Juliet," Mercutio describes his fatal stab wound as "a scratch." He knows it is more than that and that he will die. This is just one example in that play, let alone Shakespeare's other works. Plays are perfect for teaching verbal irony as they are entirely dialogue. Select scenes from a play where a character says one thing but means another. Have students identify what is actually meant by the deceptive lines.
Dramatic irony exists when the reader is aware of something a character is not. It can be difficult to spot. For example, in the classic novel "The Catcher in the Rye" by JD Salinger, the protagonist, Holden Caulfield, describes nearly every adult in his life as a "phony." Careful attention to Holden's words and actions reveals he is himself a "phony," by his own definition, as he attempts to transition from childhood to adulthood. To teach dramatic irony, have students highlight or identify information or examples of Holden's own phoniness that he never realizes himself. Ask them to explain how these examples affect Holden at the end of the novel.
The most common form, situational irony refers to a discrepancy between the expected and the actual outcome of a situation. Your students are likely familiar with the pop culture phenomenon that is the "Harry Potter" series. The seven books in the series are loaded with irony of all types, but a major plot point revealed in the seventh novel dramatically alters the reader's understanding of the entire series. Professor Snape, portrayed for six books as a villain, is revealed to have been working to protect Harry all along, despite a simmering dislike for him. Students should be able to identify this and other outcomes that are different from their logically-drawn expectations. Have them make predictions and identify expectations early in their reading, then reflect back once they become aware of the actual turnouts.
Identifying examples of irony is the first step in learning about it. Lead class discussions on why authors choose to use the different types of irony in their work and what it adds to the story. You can also use examples from popular culture of misuse of irony; for example, the hit song "Ironic" by Alanis Morrissette contains no actual examples of irony. Use the lyrics in class and have students explain exactly why each example is actually not ironic.