I can see how that might make sense. Although, wouldn't this be kind of contradictory when you take Ion's funeral scene into account, and to how the party heard Ion's voice and Tear learning the fonic hymn afterwards?

My only other concern is just that this kind of decision affects the rest of your castmates, especially Luke. You're entitled to headcanon, of course. But a heads-up might have been nice, just so everyone could be on the same page.