I don't believe there is anything supernatural about it, and (IMO) there never has been. It's a practice that probably anyone can do, with a combination of training, encouragement, and will power. Those who practice tongues certainly feel that it is "real". It gives them chills, goosebumps, even a kind of altered state of awareness, in some cases. But that doesn't mean God is doing something with them. Feelings are just feelings. Atheists can have the same feelings through other means.

Of course, there's no convincing the tongue-talker of this.

Tim