If you speak to people in words they don’t understand, how will they know what you are saying? You might as well be talking into empty space.
1 Corinthians 14:9-13 (NLT)
There are many different languages in the world, and every language has meaning. But if I don’t understand a language, I will be a foreigner to someone who speaks it, and the one who speaks it will be a foreigner to me. And the same is true for you. Since you are so eager to have the special abilities the Spirit gives, seek those that will strengthen the whole church.
So anyone who speaks in tongues should pray also for the ability to interpret what has been said.
[From this morning’s lectionary.]
Matters of Interpretation 