Glossolalia, Transcendence and Philosophical cosmology I may have replied to Amen, but perhaps he may still be able to look at this online. As far as speaking in tongues I do know people who have witnessed it, but some have thought that a lot of it may be contrived. Perhaps, it is in between, because I am sure that if we tried we could all make strange sounds, like unusual words, especially in a state of altered consciousness.
A related idea is the idea of channeling. I have a friend who is a professional artist, and she is does a lot of religious art. She told me that when she is painting and doing other artwork, she sees herself as channeling the Holy Spirit. However, I am aware that many religious people and non religious people are very sceptical of the idea of channeling. From the more traditional approach, it can be queried what entities is one channelling, and are they good or evil? Skeptics, on the other hand, often dismiss the process as being complete nonsense. The way in which I probably see it is more in connection with Jung's idea of active imagination, in which a person is getting in touch with aspects beyond the persona, and connecting with aspects such as those from the collective unconscious.