This bothers me, too. Subtitles would have been WAY better.

Where we first hear him speaking "Hive"(?) and then Ghost actively translates his words. But the voice doesn't sound right for that either. It might need more processing or something? It's hard to say.

I just kind of wrote it off mentally as Oryx possessing such a grasp on the fabric of reality that his impotent space alien rage manifests as words we understand.

Just wanted to chime in here- If you don't have subtitles enabled in Destiny, I highly, HIGHLY recommend you turn them on.

I often notice bits of dialogue that show up in subtitles, that DON'T necessarily get said by NPCs. I notice this most often vendors, say when you complete a quest or turn something in.

There are numerous times I'll complete something and the NPC will say nothing, but with subtitles on, you'll see they might have been programmed to say something.

Not sure if it's just a glitch, or if the lines maybe never got recorded, or if it's just on PS4 or whatever but give it a try and see if you notice anything.