"The one who speaks in a tongue builds up himself, but the one who prophesies builds up the church" (1 Corinthians 14:4). If you are saying something that only you understand, you are talking to yourself, building yourself up, edifying yourself, or making yourself understand. But if you are saying something that others can understand, then you are building them up, edifying them, making them understand. This is so basic that it is hard to get a hold of. The purpose of language (tongues) is communication, common understanding. So, if the language (a particular tongue) is meaningless to those who hear it, it is useless to them. Giving the benefit of the doubt, Paul suggests that it may mean something to the speaker, and so it may be useful to the speaker. But again Paul doesn't really know because he doesn't understand it.
1 Corinthians 14:5 authorizes the practice of speaking in tongues. "Now I want you all to speak in tongues...." Paul does not forbid speaking in tongues. But the question is, what does he mean? Paul uses the word "tongues" with two meanings: 1) foreign languages and 2) babbling (unknown or spirit languages). Actually, both kinds of tongues are foreign languages. One is foreign to other nationalities, and one is foreign to humanity. So, by encouraging speaking in tongues Paul is saying that he wants the gospel translated and spoken in foreign languages. He wants people to speak in languages that they know, languages other than Hebrew.
It seems that Paul doesn't mind even if someone is intent upon speaking in some unknown or angelic language. It can't hurt anything because no one knows what is being said. It might be helpful to the person speaking it, who knows? But it is at best a waste of time for the gathered body of Christ.
Paul understands that the gospel of Jesus Christ stretches the very limits of human language as people struggle to proclaim the magnitude and miracles of Christ to the watching world. Is it any wonder that Christians stutter when they try to speak about the gospel, the virgin birth, Christ's resurrection, or the Holy Trinity?
Paul spoke of groaning when he wrote to the Romans, "For we know that the whole creation has been groaning together in the pains of childbirth until now. And not only the creation, but we ourselves, who have the first fruits of the Spirit, groan inwardly as we wait eagerly for adoption as sons, the redemption of our bodies" (Romans 8:22-23). And again in his second letter to the Corinthians, "For in this tent we groan, longing to put on our heavenly dwelling, if indeed by putting it on we may not be found naked. For while we are still in this tent, we groan, being burdened -- not that we would be unclothed, but that we would be further clothed, so that what is mortal may be swallowed up by life" (2 Corinthians 5:2-4). Indeed, explaining the gospel of Jesus Christ pushes human language beyond its limits.
Is it any wonder that Christians struggle and stutter and groan when speaking of Christ? No, not at all. Paul himself groaned in frustration at the limits of language to express the gospel of Christ. Human language is inadequate to the excellencies of Christ, but we try to understand it and to explain it as best we can, trusting that the presence and power of the Holy Spirit will convey what we cannot.
And that is Paul's next point. As much as Paul wants people of every language to speak the gospel, he wants even more for them to speak with understanding, to explain Scripture meaningfully. Listen again to Paul's words: "Now I want you all to speak in tongues, but even more to prophesy. The one who prophesies is greater than the one who speaks in tongues, unless someone interprets, so that the church may be built up" (1 Corinthians 14:5). Do you hear it?
The one who speaks meaningfully is greater than the one who speaks without meaning, unless someone interprets the foreign tongue. It doesn't do me any good to hear someone speaking Russian, unless someone interprets it for me. Or we could understand Paul to say, "Speaking a foreign language is good. You all should master a foreign language. But it is even better to speak meaningfully about God's Word."
Of course! It is so basic, so simple a statement that people are tempted to read some mystical meaning into it to make it "spiritual" in some abstract, Greek, Gnostic way. My point is that the mystical meaning related to charismatic angelic languages is completely unnecessary and foreign to the text. It introduces what Paul doesn't say.
We don't have to go so far as to say that mystical glossolalia is demonic. Who knows if something is demonic or not unless they understand the meaning. Paul was just saying that it isn't helpful to the church, to those gathered. So, don't waste our time with it.
"Now, brothers, if I come to you speaking in tongues, how will I benefit you unless I bring you some revelation or knowledge or prophecy or teaching? If even lifeless instruments, such as the flute or the harp, do not give distinct notes, how will anyone know what is played? And if the bugle gives an indistinct sound, who will get ready for battle? So with yourselves, if with your tongue you utter speech that is not intelligible, how will anyone know what is said? For you will be speaking into the air. There are doubtless many different languages in the world, and none is without meaning, but if I do not know the meaning of the language, I will be a foreigner to the speaker and the speaker a foreigner to me" (1 Corinthians 14:6-11). Even musical instruments convey meaning. This is so clear. Meaning of some kind -- revelation, knowledge or prophecy -- must accompany speech. If it doesn't you may as well be baying at the moon.
I think it was Robert McCloskey who said, "I know that you believe you understand what you think I said, but I'm not sure you realize that what you heard is not what I meant." For communication to be successful there needs to be a common, agreed upon understanding of the meaning of the words spoken. If truth is relative and people are free to assign their own meanings to words, then communication will be impossible. Maybe that's what happened in the Tower of Babel.