So birds are basically just tiny descendants of dinosaurs, right? Parrots, corvids, and a few others are capable of mimicry.... were there any dinos that shared that trait?
Dude from Jurassic Park: "Clever girl..."
Raptor: "CLEVER GIRL! raptor bark sound thing CLEVER GIRL!" eats his face
bear in mind that birds are a specific branch of dinosaurs, closest related to stuff like velociraptor.
so it's a pretty good bet that raptors would make bird-like noises (though probably less complex and lower pitched), but doubtful that a stegosaurus would sound anything like a bird.