Yes, but unlike you I recognize these voices as different branches of myself or my psyche and not as entirely separate entities. I honestly don't take more than a grain of salt when it comes to things like "multiple personalities". Is it possible? Yes, just like Big Foot and El Chupacabra, but I still see it as a coping mechanism in which people who have repressed their innate desires start to lose control and these innate desires start emerging in various forms. Maybe it's them or their subconscious, but I believe something within themselves has made them think these "voices" and "personalities" aren't coming from them. Have you thought about that? Maybe you are doing something to sabotage your mind-frame? It could be spontaneous or stem from some sort of trauma. Or it could be exactly what you stated it to be.