Most of the people have trouble speaking coherently in English. How do you know that they are any better at tongues?
One of the basics of the Bible is that God is not the author of confusion. And that is what speaking in tongues does - it creates confusion. People get weirded out by it because they don't understand it. That makes it a little bit suspect right there.
I'm not saying that it's wrong, but I definately have no urge to speak in a non-intelligible language.