If birds came from dinosaurs, did dinosaurs sing?

They probably vocalized and communicated that way, but didn’t sing per se. Songbirds evolved significantly later on: there’s plenty of families of birds that don’t sing.

They were definitely vocal. Hadrosaurs like Parasaurolophus had complex crests and nasal passages to make calls with. The smaller species would probably have sounded quite birdlike.

Fun fact- we now know birds didn’t come from dinosaurs, birds are dinosaurs.

Imagine a meteorite hits tomorrow and kills 90% of life on earth- the only mammals left are bats. No people, no monkeys, no elephants, tigers or whales. Just bats. Also all the birds are dead so the sky is 100% bat territory.

That’s essentially what happened the K/T extinction.

But yeah, nonavian dinosaurs most likely had impressive vocal ranges.

How do movies like Jurassic Park know what dinosaurs sounded like, if no one’s ever heard them?

Only when they were playing the ukulele.