For if I pray in an unknown tongue, my spirit prayeth, but my understanding is unfruitful. What is it then? I will pray with the spirit, and I will pray with the understanding also: I will sing with the spirit, and I will sing with the understanding also. Else when thou shalt bless with the spirit, how shall he that occupieth the room of the unlearned say Amen at thy giving of thanks, seeing he understandeth not what thou sayest? For thou verily givest thanks well, but the other is not edified. I thank my God, I speak with tongues more than ye all: Yet 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. ~ 1 Corinthians 14:14-19 

Paul speaks of praying in an unknown tongue and refers to this as praying with his spirit. For if I pray in an unknown tongue, my spirit prayeth. Paul goes on to speak of praying with his understanding as well. He explains that this is for the benefit of others because they wouldn’t be edified if they don’t understand what is being said. Even though the one speaking in tongues give thanks well, the others present wouldn’t be edified. Paul then says to the Corinthians I thank my God, I speak with tongues more than ye all.

This statement is a reference to Paul’s private prayer life. We can be certain of this because he follows this statement saying, Yet 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.

In contrast to his much speaking in tongues, I thank my God, I speak with tongues more than ye all, Paul’s desire was the edification of others in public assemblies. Speaking in tongues serves two purposes in the life of the believer. First, it serves the purpose for personal edification in the believer’s private prayer life and devotion to God. Evidently, Paul prayed much in other tongues because he claims he spoke with tongues more than all the Corinthians put together.

Secondly, tongues serves the purpose of edifying the body of Christ when it is coupled with interpretation in a public assembly. Thus, tongues with the interpretation equals prophesy. If there is no interpreter present, the believer should exercise restraint and keep his speaking in tongues between him and God. But if there be no interpreter, let him keep silence in the church; and let him speak to himself, and to God. ~ 1 Corinthians 14:28

The Corinthians did not need correction because they spoke with tongues, they needed correction because of their misuse of tongues in public assemblies where others who were unlearned or unbelievers might be present. 1 Corinthians 14 is not a chapter discouraging speaking in tongues, it is a chapter encouraging the proper use of tongues.

Are there some people today who claim to have the gift of tongues but do not? Without a doubt, but the false does not disqualify the real. In his second letter to the Corinthians, Paul speaks of another gospel, another Jesus, and another spirit. These do not disqualify the true. Likewise, counterfeit tongues do not discredit the genuine.

it’s important to understand that the Corinthians were not displaying counterfeit tongues, but misusing the genuine.

That which is real and authentic can be misused. This was the case with the Corinthians. They had a lot of things wrong and the misuse of tongues in public assemblies was just one of them. In his letters to the Corinthians Paul also addresses their tolerance for fornication, their mishandling of the Lord’s Supper, their lack of discretion regarding food offered to idols, their propensity to be deceived by false apostles, etc. In fact, Paul’s mention of another gospel, another Jesus, and another spirit is in context to his rebuke of their giving in to false apostles.

The Corinthians were carnal believers, who had not matured in the faith. Consider Paul’s words regarding their carnality.

And I, brethren, could not speak unto you as unto spiritual, but as unto carnal, even as unto babes in Christ. I have fed you with milk, and not with meat: for hitherto ye were not able to bear it, neither yet now are ye able. For ye are yet carnal: for whereas there is among you envying, and strife, and divisions, are ye not carnal, and walk as men? ~ 1 Corinthians 3:1-3

Paul was a spiritually mature man who prayed much in tongues in his own personal prayer life. The Corinthians were carnal and in their carnality they were not considerate of others in their use of the gift of tongues when they gathered in public assemblies. Yet Paul does not tell them to shut it down. He gently instructs them and corrects them regarding the proper use of tongues, as well as prophecy, and then tells them, Wherefore, brethren, covet to prophesy, and forbid not to speak with tongues. Let all things be done decently and in order. ~ 1 Corinthians 14:39-40