Final answer:
Dramatic irony occurs when the audience knows something the characters do not. Theme is the underlying message of a story. Dialogue plays a critical role in a play by moving the plot, describing behavior, providing characterization, and revealing thoughts and feelings.
Step-by-step explanation:
Dramatic irony is when the audience knows something that the characters do not. For example, in a play, the audience might be aware that a character is planning a surprise party for another character, but the character being surprised is unaware. This creates tension and often leads to unexpected outcomes.
Theme, on the other hand, is the underlying message or point of a story. It is the broader idea that connects the plot, conflicts, and characters. For instance, a theme in a story could be the importance of friendship or the consequences of greed.
Dialogue plays a critical role in a play as it keeps the plot moving, describes how the characters behave, provides direct characterization, and reveals the characters' thoughts and feelings. It is through dialogue that the audience gains insight into the characters and their motivations.