I've been studying the matter of speaking in tongues. 1 Corinthians 14 really seems to cover the matter in depth. And there is some insight in Romans 8 as well...
Here is what I have concluded: The Holy Spirit will intervene for us when we do not know what to pray. Actually, the way it is written, Paul implies that we don't ever really know exactly what to pray for!
Romans 8:26 Likewise the Spirit also helpeth our infirmities: for we know not what we should pray for as we ought: but the Spirit itself maketh intercession for us with groanings which cannot be uttered.
That seems as though it could be a reference to the "prayer language," or to tongues. Paul does not forbid the speaking in tongues in the church--but he unquestionably discourages it.
18I thank my God, I speak with tongues more than ye all:
19Yet in the church I had rather speak five words with my understanding, that by my voice I might teach others also, than ten thousand words in an unknown tongue.
So if someone is going to insist on speaking in tongues while in the church, there should be someone there to tell the congregation what the prayer was. The problem seems to arise when the interpreter indicates that the tongue spoken was a divine message from the Holy Spirit to the congregation. This does not appear to be what Paul would condone as the proper use of tongues.
Some churches believe that divine revelations come through certain of their members in the form of tongues. This does not seem to be supported anywhere in scripture either. When someone stands up during a chruch service and begins speaking in tongues, and another interprets that language as some prophetic message for the church, that does not appear to be the proper use of tongues, and is much more likely just someone uttering psycho-babble and another "interpreting" because that's what Paul says to do. But the thing is, they do not appear to have read and understood all of what Paul had to say about the matter.
Again, there seems to be no scriptural support for the notion that God speaks to us by the use of tongues. (If I'm wrong about that, please refer me to the proper place in scripture and I'll have a look at it). So, tongues are for the purpose of praying "when we do not know what to pray," and preferably when not attending services.
An aside: I think the reason that Jesus Himself never was reported to have spoken in tongues is that He would certainly not have ever been at a loss for words. But of course as mere humans, we do often have trouble with selecting the right words, or singular thing to pray for. A "prayer language" here might be useful. I have never prayed in tongues. But I'm not totally opposed to the idea...
I believe that the tongues spoken of in Acts at Pentecost were divinely inspired so that foreign peoples could hear the gospel in their own language. So in this case, the tongues were of men, not angels; they were foreign languages. It should be mentioned, however, that Paul does refer to "tongues of angels" in 1 Corinthians 13: 1Though I speak with the tongues of men and of angels, and have not charity, I am become as sounding brass, or a tinkling cymbal.
If it were ever expedient and necessary in this day and time, I'm sure the Spirit would do the same thing again, which is to give a person the ability to speak French (for instance) if a French person had never heard the gospel and was in dire need of hearing it right this instant. I think that speaking in tongues in the days of the apostles was much more useful and necessary then than now, because The Word has been communicated all over the world now, and is printed in every conceivable language. What we see in some charismatic churches is much like what must have been going in in the Corinthian church, and which obviously drew Paul's scorn. I'm speaking of an over-zealous wish for the gifts of the Spirit, at the expense of order, and often, it would seem, truth itself.
I do believe that speaking in tongues is a gift of the Spirit. However, it is unfortunate that it appears to be the most easily faked of the gifts. ;)
Dan