Translation
Therefore, the one who speaks in a tongue
Go to footnote numberlet him pray that he may interpret. (See comment below.)
Go to footnote numberParaphrase
You may say, “What we are doing could easily fit the rules if the person who prays in tongues can also share an interpretation. So, all we need to do is seek an interpretation, and everything will be fine. Right?” (See comment below.)
Footnotes
1: Which type of tongues is Paul talking about?
Is Paul talking about public tongues, proper private tongues, or the counterfeit? He is talking about the counterfeit because verses 14, 16 and 17 are a continuation of this thought and clearly refer to their practice of praying out loud in tongues at a meeting of the congregation.
2: Why did Paul say "Let him pray that he may interpret"?
When we apply the clearly stated rules that govern spiritual gifts, we can discern when Paul was speaking truth, and when he was mimicking their falsehood for the sake of argument. In this case, I am convinced that something akin to ridicule is the only proper interpretation because what they were doing was a violation of God’s rules over such things. A true interpretation of a false tongue is an oxymoron.
So why did Paul tell the person to pray for the interpretation also?
First of all, Paul was anticipating that their defense of their style of tongues would be that if a person received the interpretation of his own tongue, it would become a blessing to others and thus fit the rules. Here Paul mimics what he thinks their defense will be in order to expose the ridiculousness of what they were doing. That the troublemakers in Corinth would receive some kind of interpretation from the Holy Spirit was impossible because they were not engaged in a true form of tongues given by the Holy Spirit. A true interpretation of a false tongue is an oxymoron. Of the three types of tongues, true public tongues, true private tongues, and the twisted hybrid of public and private tongues invented at Corinth, only one required interpretation on some occasions, and that was true public tongues. If someone spoke an interpretation to the counterfeit form of tongues, it was not from the Holy Spirit.
Paul was showing the troublemakers that they should keep quiet. But that was not an acceptable option in the minds of those using the counterfeit because it would mean no glory for the glory-seekers.