Wittgenstein was pretty sceptical of the idea that anybody had even *one* personality, let alone multiple personalities.

The cases of MPD I've read about, the personalities don't really communicate with each other. One just displaces another.

It just occurred to me that there *must* be video on the web of glossolalia - a YouTube search for that or "speaking in tongues" or terms relating to Pentecostalism ought to produce something. (Right now I'm on a computer that can't do YouTube). The only Pentecostalist I've heard doing it was also schizophrenic, and what he came out with wasn't a very convincing imitation of a human language. (Linguistic studies of "speaking in tongues" show that the speech produced uses a much more limited and stereotyped range of sounds than any real language).