Participatory Spirituality for the 21st Century
At FB Balder linked to this article. I recently saw a preview of Glass the movie. The same character from Split is in it, as well as the previous movie Unbreakable. One character has split personalities to the point of schizophrenia, but we all have these different voices from our past in our head: Parents, teachers, different points in our own lives, etc. It can become a healthy psychological practice to acknowledge and engage them when they arise. There is no need to find metaphysical sources for them. Exteriorizing them like that just might facilitate schizophrenia.
This article on inner dialogue, "the voices in our head," highlights that it's a common phenomenon. And it does have a verbal quality, as if we hear it, at least in our thoughts. It "involve[s] representing the point of view or the perspective of another person." Vygotsky noted how in our development we internalize our external dialogues with others, particularly caregivers. Our self talk is social in nature.
This is distinguished from auditory hallucinations, which is considered mental illness. And yet even those, according to the topic article, can be considered healthy in the right context.
Btw, I put it in the 'engagement' sub-forum as it involves engaging with others through our internal dialogue. As Captain Picard is fond of saying: Engage!