Questions & Answers about Ze hebben een affaire, en iedereen heeft het erover.
Why does this sentence use heeft het erover instead of just translating "talks about it" as praat erover?
Het hebben over is a highly frequent idiomatic expression meaning "to talk about" or "to discuss" a topic. While praat erover is perfectly correct, het hebben over is often preferred in everyday conversational Dutch when referring to the subject being discussed.
What is the grammatical function of het in heeft het erover?
In this sentence, het is a lexicalized (or "dummy") pronoun. It does not replace a specific noun from the first clause, like the affair. Instead, it is a permanent, fixed part of the verb phrase het hebben over. You cannot drop it.
Where does erover come from in this sentence?
The expression requires the preposition over. Because the sentence means "everyone is talking about it" (referring to the affair), Dutch grammar requires turning the preposition + het ("about it") into the pronominal adverb erover. You cannot say over het here.
Could the word order be iedereen heeft erover het?
No, that word order is incorrect. As a direct object pronoun, the dummy het must be placed directly after the conjugated verb heeft (and the subject iedereen). The pronominal adverb erover always comes later in the clause.