Generally the junk you see on TV or online of people "speaking in tongues", is just that: Junk.
But really speaking in tongues, is more like meeting someone from India, and speaking to them as if you were both speaking the same language.
This is why in the book of Acts chapter 2; it talks about how there were a bunch of Jews gathered together from all different nations, suddenly able to understand each other, without an interpreter. It is a supernatural event, something unable to be explained. I wouldn't even begin to speculate on the mechanics behind it, but I trust the source of that "Holy Spirit" which can do things like this.
I mean, there's a scientific explanation for how the universe exploded from nothing, but it really isn't all that scientific. Nothing doesn't just explode, does it? That sounds more like magic than science. You might as well just say, "God did it."
Not everything can be rationally explained, and love is one of those things. How do you rationally explain a God who personally died for the sins of the entire world? Jesus was either crazy, or, really was God. There's no middle ground, so either miracles like speaking in tongues is possible even if not explainable, or it's just a lie.
Well, to believe it is a miracle, you'd first have to drop the need for a scientific explanation, but I suppose it wouldn't be any different than some of those futuristic shows that have something like a "universal translator". Why wouldn't God be able to do something like that, if God really does exist?