ok guys. the way it works is this. someone (usually a pastor), not some joe schmoe, can begin speaking in tongues. what happens is, they speak in tongues for a few seconds, then they start speaking in a language the general population will understand. they do this to interpret the words you just heard which sounded like "gibberish" to you.
when someone speaks in tongues, and doesn't interpret what he or she was just saying, then, that person is usually lying.
the purpose of speaking in tongues is very simple. just like some of u go to psychic's to find out whats gonna happen in the future. well, there is a higher power supreme to that of the psychic, which knows everything. that higher power is the holy ghost.
if u r a devout person, or someone who frequents the church a lot, and u have some type of calamity in your future, when these pastors start speaking in tongues, they will usually foresee it and will warn you about it. the pastor may request to speak to you after church if the issue is of a sensitive nature. these pastors, the truly legit ones dont ask sh1t from u. they dont ask u to pay nothing. thats all up to you. when what the pastor predicts comes to past, if u are a grateful person, u'll know to offer your thanks to the man of god in ways you feel is appropriate. you can buy him anything. or u can not. it's up to you. but if u have any common sense, you'll know not to fucck around with the messenger of the most high.
in other words, the whole concept of speaking in tongues is to relay a message from the holy spirit, through the man of god, to the general population. those u see dancing around and making a fool out of themselves have a judgement reserved for them.