They don't. They can only guess. As far as I know, no dinosaur fossil has ever been found with a hyoid bone, which is part of how we're able to make noise and speak. That doesn't mean they couldn't make sounds. It's quite likely they could, at least some of them. Think less high pitched chirping ala birds today, and more hissing, rumbling, and trumpeting.
I_AM_A_CLICHE_IKNOW t1_jefjf4d wrote
Reply to Eli5: how do scientists know how dinosaurs sound? by ComputerUpbeat1714
They don't. They can only guess. As far as I know, no dinosaur fossil has ever been found with a hyoid bone, which is part of how we're able to make noise and speak. That doesn't mean they couldn't make sounds. It's quite likely they could, at least some of them. Think less high pitched chirping ala birds today, and more hissing, rumbling, and trumpeting.