So to give a quick description, this is a 2 mile long, nuclear powered dragon of doom. I think I’ll going with a fission/fusion hybrid creature for this beast. Another piece of relevant information is that all dragons in this universe utilize pretty much all metals as structural substrates. In fact, barring very advanced technology, their corpses are the only source of dragon steel.
So the idea here is that the dragon uses metals in its sinuses and other resonance chambers to increase the variety of sounds it can make, along with the volume of the sounds. I had also thought about the possibility of the dragon using partially metallic vocal chords.
However, the question is why? What could they use this vast array of sounds in varying pitches and volumes for? Most intelligent creatures can get by with making just a few noises, so why would these dragons need such a vast array of sounds?