NOBODY knows what dinosaurs sounded like. Edison wasn't around then. We can't even make a good guess because we don't have the soft tissues and muscles of the larynx or syrinx. Because dinos are big birds, we can imagine that they might have peeped or cawed, but modern birds have such a wide range of sounds that we can't guess which end of the spectrum is more valid.
The current icon shows Polistra using a Personal Equation Machine.