Just a correction on this one, it is this way NOW, but "speaking in tongues" was originally when one person started speaking a foreign language, and there were people who didn't speak his native language, but that foreign language, that could understand him. It happened as a miracle to make translators obsolete. Funny how things change...


ANYWAY, I think - and this is my own personal theory with no basis in any training, or concrete fact - that it's caused by the subconscious being able to come out. Our subconscious is really quite amazing, and can learn things far faster. Admittedly, the person would have have to have some contact with the language, but theoretically their subconscious learning of that language could come out and it would look like they'd "suddenly" learned a new language. I can't imagine it would last very long through.