If you are referring to the fact that the word unknown in front of tongues was added by the translators, and is therefore a mistranslated verse here:

If any man speak in an [unknown] tongue, [let it be] by two, or at the most [by] three, and [that] by course; and let one interpret.  1 Corinthians 14:27-28

That was to avoid this:

If therefore the whole church be come together into one place, and all speak with tongues, and there come in [those that are] unlearned, or unbelievers, will they not say that ye are mad?  1 Corinthians 14:23

This is only in the church.   Paul addressed the [unknown] tongue (really a tongue which no one understands but God) and validates it here:

For he that speaketh in an [unknown] tongue speaketh not unto men, but unto God: for no man understandeth [him]; howbeit in the spirit he speaketh mysteries.  1 Corinthians 14:2

He even tells us specifically not to forbid it which means that he approves it and as you can see here many people back then were already starting to forbid it, just like today in the modern day church.

Wherefore, brethren, covet to prophesy, and forbid not to speak with tongues.  1 Corinthians 14:39

Are you aware that there are several different kinds or “diversities” of tongues and an “unknown” tongue in the church is just one of them (1 Corinthians 12:28)?  By the way, unknown to who?  Certainly not unknown to God.  So then how would you discount new tongues as Jesus himself said in Mark 16:17 that it was a sign of them that believe?  So then anyone who does not speak in new tongues must not believe, right?

How do you discount the apostle Paul who said that he thanked God that he spoke more in tongues than any of the believers (1 Corinthians 14:18)?  Paul also taught how to speak in tongues properly in the church.  Paul said that he prays in the spirit (tongues) and with the understanding.  Even singing in the spirit!

And that when you pray in the spirit, you give thanks well (1 Corinthians 14:15-17).  Jude the half-brother of Jesus even said to build yourself up in your most holy faith praying in the Holy Ghost which is in tongues (Jude 1:20).

I can give you an example of tongues that you have never heard of before.  I play guitar and was invited to come and play in a Haitian Christian Ebenezer church.  I was running a bit late and when I arrived they had already started the service but not the music yet.  So I quickly sat down, took out my guitar and started playing along.  All of a sudden I realized that I had not tuned up to E and that I was still tuned to Eb (E flat) which is what I usually play in for myself.  What could I do?

I couldn’t tune in the midst of a song.  So I tried to transpose and play a half step up.  But it did not sound right so I stayed in key and wondered what on earth was going on.  Then it suddenly hit me.  The Holy Spirit was translating the chords a half a step up while my guitar was still tuned a half a step down.  In between songs I would check my tuning and sure enough it was still tuned to Eb.  This lasted all throughout the service and when it was over, it was still tuned to Eb.  Now that is tongues for you!  I love it when God colors outside the lines.

The idea at pentecost was to translate the praises of the apostles to all the foreigners who were visiting Jerusalem so they could hear them in their own language.  This still happens today in many foreign countries and even here with foreigners.  But if that is all, then it was just a limited gift.

As I described before, it is also a powerful personal two-way communication tool between you and God direct that is private and the enemy cannot intercept it.  Like a fiber optic cable, it is both upload and download at the same time.  If you are wondering why you are not getting the revelations you want, then you are not communicating on a secure channel.  It was also prophesied and called the refreshing for the believers (Isaiah 28:11-12 & 1 Corinthians 14:21)  It is also there when you come to the end of your prayers in English and helps you in your weakness of praying in the understanding when you know not what to pray (Romans 8:26).

The cloven tongues of fire as well as the wind rushing through the place was for the believers to realize that something was happening (Acts 2).  It says that all of them were filled with the Holy Ghost and they began to speak with other tongues (Acts 2:4).  They had to open up their mouths for it to happen.  God did not open their mouths to force them to speak with other tongues.  If I picture it I see them starting to praise God for what was happening and as they opened their mouths and began to speak they started speaking in other tongues.  Notice that they were the ones who had to start it.

Another quick story about tongues: a small Mennonite church in Pennsylvania decided to have 3 days of fasting and prayer both in the spirit and with the understanding.  One night a fire truck showed up and the firemen stormed into the church much to the bewilderment of the praying attendees.  The firefighters were just as bewildered and when they asked them how they could help them they blurted out “Where’s the fire? We see flames on the roof but we don’t see any fire in here!”

There are many sacred cows in the modern-day church.  It is our task to slaughter every one of these or they will trample all over correct doctrine and destroy our faith.