To the Corinthians, Paul was showing that tongues is prayer, praise, and the giving of thanks. Many times there will be no interpretation:
 
"Else when you bless with the spirit,[in tongues] how shall he that occupies the room of the unlearned say 'Amen' at your giving of thanks seeing he understands not what you say?" 1 Cor. 14:16

The above verse does not make an allusion to earthly languages. The phrase, "he that occupies the room of the unlearned" is not to be interpreted as, "a foriegner that does not know the language (dialect)" The Greek word, "idiwtou" is what has been translated as, "unlearned." The English word, "idiot" stems from the word, "idioc/idiwtou" The word has such definitions as, "amateur," and, "unknowledgable," (but it is not defined as "foriegner"). In the above verse, it is seen that tongues is praise, that is, blessing the name of God, which is the giving of thanks. Paul's next verse supports this:
 
"For you verily give thanks well,[in tongues] but the other is not edified." 1 Cor. 14: 17 

Tongues for Praise in Acts

Two portions from the book of Acts substantiate that tongues is for praise, rather than for evangelism:
 
First: "While Peter yet spake these words, the Holy Ghost fell on all them which heard the word. And they of the circumcision which believed were astonished, as many as came with Peter, because that on the Gentiles also was poured out the gift of the Holy Ghost. For they heard them speak with tongues, and magnify God" Acts 10: 44-46 In what has been called the "Gentile Pentecost" at Cornelius' house (above), people were speaking in tongues; but not to evangelize, but rather, to "magnify God." There probably were not any earthly dialects spoken at Cornelius' house, as there were no foriegners there to hear it. In fact, there were few people there, and they must have all spoken the same dialect because they were all either friends or relatives of Cornelius: "And Cornelius waited for them, and he called together his kinsmen and near friends [no one else]." Acts 10:24
 
Second: In Acts 19, it is written that Paul met some faithful Jews who believed in John's baptism (a baptism signifying repentance of sins while awaiting the arrival of the Messiah). When Paul told them of Jesus and laid his hands on them they spoke in tongues. But they were not speaking tongues to evangelize foriegners; they were simply prophesying. And once again, there were few people there--no foriegners were present to hear in their own dialects: "When they heard this, they were baptized in the name of the Lord Jesus. And when Paul had laid his hands upon them, the Holy Ghost came on them; and they spake with tongues, and prophesied. And all the men were about twelve." Acts 19: 5-7 

Corinthian Tongues

When Paul was writing to the Corinthians, he was trying to show them that there were different kinds of tongues, and that the tongues-speaking in the church needs to be interpreted or spoken qiuetly--or silently. This author believes that "qiuetly" is a good interpretation of verse 14: 28 (below), because in relation to everyone else; the "quiet" tongues speaker is basically, "silent," and not disrupting the church service--but let the reader decide:

"But if there be no interpreter, let him keep silence in the church; and let him speak to himself, and to God."1 Cor. 14:28

Concerning verse 28, above; and by reading it in context (from verse 26 to verse 33), it is seen that it is only during the portion of the church service that is set aside for prophetic speaking that the tongues-speakers should be quiet (keep silence), but only if there is no interpreter. However, those verses do not prohibit qiuet tongues-speaking during the prayer/worship/singing portion of the service. For just as today, people may be heard quietly praying in their own language (during the prayer/worship/singing part of the service); so, also, people may be heard quietly praying or singing in tongues during the worship. 

To reiterate: There is a portion of the church service when prophetic speech is to be heard as messages from God to the congregation. During this time of the service, there should be no loud tongues-speaking without the accompanying interpretation. The interpretation would then be known as “knowledge” or “teaching” or a “revelation,” or a “prophecy” for the benefit of the church. Paul explains the necessity for interpretation in the verse below:
 
"Now brethren, if I come unto you speaking with tongues, what shall I profit you, except I shall speak to you either by revelation, or by knowledge, or by prophesying, or by doctrine [teaching]?” 1 Cor. 14: 6
 
And it is also important to reiterate that today tongues speakers may be heard qiuetly praising God during the church service (but during the” praise” portion of the service) with no need of an interpreter; as they are simply praying by themselves, to God; and just as one might hear another qiuetly praying to God in the normal language while rest are singing a praise song; so one might also hear another praying or singing qiuetly in a tongue while the rest may be singing in the normal language; that would be "to himself and to God" and it would not disrupt the service. Paul would certainly approves of this, as he says:
 
"What is it then? I will pray with the Spirit [tongues] and I will pray with the understanding [normal language] also: "I will sing with the Spirit [tongues], and I will sing with the understanding [normal language] also." 1 Cor. 14: 15

This means that there is going to be singing within the worship service and it will not always be the normal language; sometimes it will be in tongues--just so it does not disrupt the service. However, there will be times when a tongues-speaker will speak a tongues-message outloud—even before he knows whether or not someone will give the interpretation (that is an implication of verses 27, 28 below):

"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. But if there be no interpreter, let him keep silence in the church; and let him speak to himself, and to God. Let the prophets speak two or three, and let the others judge. If anything be revealed to another that sitteth by, let the first hold his peace. For ye may all prophecy one by one, that all may learn, and all may be comforted. And the spirits of the prophets are subject to the prophets. For God is not the author of confusion, but of peace, as in all churches of the saints." 1 Cor. 14: 27-33
 
But if there turns out to be no interpreter then the loud tongues need to be quieted (he can then speak, "not unto men, but unto God" 14: 2). But there might be a tongues message spoken before the speaker knows if it will be interpreted or not; or why else would Paul say,"Wherefore let him who speaks in an unknown tongue pray that he may interpret" (1 Cor. 14: 13).
     It may be, that if a tongues-speaker gives a message that is not interpreted, then the rest of the tongues-speakers should not bother to give a message unless they know that they will be able to interpret it themselves. However, if a church sets apart a (prayer) service just for praise, worship, tongues, and prophecies; then do not let cessationists stop the service from having a hundred or more tongues-messages--with and without interpretations.
 
The cessationis argument (that the prophetic gifts have already ceased) is the result of a lack of in-depth study of 1 Corinthians. Cessationists write volumes on every theological issue imaginable; such as, "How tall the jars were that held the water that Jesus turned into wine," or the, "The Regulative Principle" (That is, the possible outlawing of musical instruments in worship). But when it comes to the topic of the different kinds of miraculous tongues that God supplies, suddenly they do not want to investigate anything. Instead of studying, they simply say, "tongues were always foriegn languages and died out..Bye."

The cessationist argument does not come from studying the Holy Bible; rather, it arises out of a misunderstanding of the nature of prophetic speech. Cessationists state their overly-simplistic line of reasoning in three steps; as follows:

First: "Tongues and prophecies were God's Word to the church."
Second: "The Holy Bible is God's Word to the church."
Third: "Therefore we no longer need tongues and prophecies as God's Word to the church, because we now have the Holy Bible as God's Word to the church."
 
After stating these three points they usually go on to say, "Prophetic speaking was only needed until the Holy Bible was written, and now that we have a complete Holy Bible, there is no need for further revelation." And their argument often concludes with these words: "For all we need to know about salvation, prayer, holy living etc. is preserved for us in the complete inerant Word--the inscripturated prophecy. What need is there for additional revelation?"
     The cessationist confusion lies in that they do not know that tongues and prophecies serve a different purpose than the Holy Bible does. Prophetic speech does not take the place of the Holy Bible; rather, we are given both. For instance, the Holy Bible states that people need to work; but a tongues-interpreted or a prophecy can say what particular job a person should work--or where he should live etc.
      Now, Pentecostals do believe that the Holy Bible is complete and inerrant; but it does teach Christians to follow extra-Biblical revelation--such as dreams, visions, tongues, and prophecies etc. Paul is adamet against cessationist teaching. He ends three chapters of discusion about spiritual gifts, with these words:

"Wherefore, brethren, covet [zeloo] to prophesy, and forbid not to speak with tongues." 1 Cor. 14: 39

It will be mentioned that in the above verse, and in 1 Cor. 14: 1(below), the Greek manuscripts contain the word "zeloo" which means, "zealous, strong desire." Christians are commanded to desire exceedingly and seek with a passion, to have spiritual gifts. In the verse above, the word "covet" is the translation of zeloo. In the verse below, the KJV decided not to translate the word, “zeloo,” but other translations have it.
 
"follow after charity, and desire [zeloo] spiritual gifts, but rather that ye may prophesy." 1 Cor. 14: 1
 

Tongues and Prophecies continue

In closing; it will be noticed in the verses below, that contrary to cessationist thinking, Paul taught the Corinthians that prophetic speaking will be manifesed in the churches until Christ returns to earth.
 
"I thank my God always on your behalf, for the grace of God which is given you by Jesus Christ; that in every thing ye are enriched by him, in all [prophetic] utterance, and in all [prophetic] knowledge; Even as the testimoney of Christ was confirmed in you: so that ye come behind in no gift; waiting for the coming of our Lord Jesus Christ: Who shall also confirm you unto the end, that ye may be blameless in the day of our Lord Jesus Christ," 1 Cor. 1: 4-8

Some might object to the insertion of the word "prophetic" in verse 5 (above), as ”prophetic” utterance and “prophetic” knowledge. But that is the plain meaning of the text as Paul is speaking to the Corinthians of spiritual gifts. Also, the Greek word, "charis," that is translated as "grace" in verse 4 (above) is not only used for "salvation-grace," but that same word is used by Peter and Paul; in Rom. 12: 6, Eph. 4: 7, and 1 Peter 4: 10 to describe spiritual gifts.
     Paul must be writing to the Corinthians of their "prophetic" speaking (that he is thankful for), because their natural speaking was nothing but contentious ego-centered quarelling. According to numerous commentaries, the Corinthians normal speaking was nothing but fighting. It cannot be possible that Paul was thankful they were enriched in that kind of speech; rather, Paul was thankful for the "grace" for spiritual speaking and knowledge, which is prophetic.
      Now if it is argued, based upon Paul's words: "ye come behind in no gift; waiting for the coming of our Lord Jesus Christ." that Paul is not authorizing the use of prophetic speech until Christ returns, then it may also be argued that he is not authorizing the use of the Lord's Supper until Christ returns either; as that teaching is based upon identical language:  

"For as often as ye eat this bread, and drink this cup, ye do shew the Lord's death till he come"  1 Cor. 11:26