If your approach to the subject is that it's the same as the "what if our 'reds' are different" debate then yeah it's going to be unfalsifiable, you've also jus

If your approach to the subject is that it's the same as the "what if our 'reds' are different" debate then yeah it's going to be unfalsifiable, you've also just very generously assumed from the get go that I'm conflating ideas plus ignored the end of the prior comment. My friend cannot create a mental voice at all, so not only does he not usually talk to himself mentally, he never does it. He also can't recall voices. If someone is describing a process in steps he has to stop them frequently to write down the parts. This doesn't apply to a process he's seen, he can recall imagery fine. The end of the very last comment I made contained a possible method for comparing these different thought processes, giving someone with poor mental imagery a spatial task and comparing with someone who claims strong mental imagery, the idea being that intuition should be faster under one set of conditions than the other. Funnily enough there's also others in this thread who have mentioned using imagined images to navigate spatial tasks.