Question tags are short questions added to the end of statements. They are used in speech to confirm something is true or encourage a reply. Question tags have the opposite polarity of the main statement - a positive statement takes a negative tag and vice versa. There are specific rules for forming question tags that depend on verbs, tenses, subjects, and word order between the main statement and tag. Question tags follow a standard format and set of rules to confirm information or elicit a response from the person being spoken to.