The only thing I can think of that this could refer to is split brain patients who have undergone a specific medial procedure once used to treat epilepsy. It's possible, although not well understood, that the two halves of their brain operate sort of independently, and only one has access to speech.
It's a very interesting topic, well worth diving into! But it's also very muddy, there is contrasting evidence for and against the "two mind" theory.
Anyway, I'm fairly certain this "theory" does not apply to healthy brains which have not undergone this procedure.
If you're interested I highly recommend this evidence review on the topic. I don't remember the details but there does remain some compelling evidence for both sides. It seems like the two halves are able to communicate in some ways, but not in others. It's not fully clear if this means there are two distinct consciousnesses, or if they continue to operate as one.
Well I'll be, still I think "Still continue to operate as one" makes less assumptions, we barely know consciousness is even real to begin with, how can we confidently say that it's like an infinitely dividable amoeba of some kind? I guess I'll check the link.
Yeah I think that's what's so interesting about it! It's one of the few situations where we have been able to (in a limited way) study how consciousness comes about in a mind. Perhaps leaving us with more questions than answers... Tantalising.
It certainly feels like that at times. The key being the non verbal part, it's the part that feels things i can't explain, like I have to poke and probe some part of my brain by imagining, to try and see how it reacts to certain thoughts and observe the emotions, then try to put it into words to explain it to the conscious part of my mind. Like, the subconscious is not unconscious, it's perfectly conscious just not verbal.