Tag questions are short questions added to the end of a sentence to confirm information or seek agreement. They usually consist of an auxiliary verb and a pronoun, like "isn't it?" or "didn't they?" They are used to confirm information or seek agreement. If the main sentence is positive, the tag is usually negative, and vice versa. For example, "You're coming, aren't you?" These are often used in spoken English for politeness or to involve the listener in the conversation.