The texts in question are found in 1 Corinthians 14. Let us look fully at the context of chapter 14 to clearly understand the Apostle’s instructions to us. Verse one is simply stated; pursue love first, then as regarding spiritual gifts, prophesying (“speaking under inspiration”, G4396) is to be the most desired. 

Verses two through five are where the question above seems to focus.  Here the word tongue is from  Strongs word G1100, languagenaturally un-acquired. If the person speaking in another language could understand (his own words) as well as God could, then only that person would be edified. Another person would need to translate so others could also be edified. How else would anyone be benefited? (Verse five instructs that someone should interpret.) On the other hand, if one were to prophesy he would edify those who heard, exhorting and comforting them. Prophesying would allow everyone to be benefited.

Verses six through 11 concur with this thought. I Corinthians 14:9 (English Standard Version), “…if with your tongue you utter speech that is not intelligible, how will anyone know what is said? For you will be speaking into the air.”

Verses 12-20 instruct us to pray, that with whatever gift we have received, we may fully understand it and use it correctly. The gift should be edifying to the whole church, otherwise it will be unfruitful or unproductive.  It speaks of not being undeveloped as a child would be, unskillful in the Word of the Lord, but in humility, praying to understand the wisdom of God in the use of these gifts. We are not to boast of the gifts or think somehow we are better than one another because of them, for as 1 Corinthians 4:7 (KJV) expresses it, "For who maketh thee to differ from another? And what hast thou that thou didst not receive? Now if thou didst receive it, why dost thou glory, as if thou hadst not received it?" 

Verses 21-23 are a direct fulfillment of a prophecy found in Isa 28:11 (KJV). "For with stammering lips and another tongue (language) will he speak to this people." This was to be a great sign to the unlearned and unbelieving of Israel, proving that the Gospel teachings were of God (Compare Acts 2:3-11). 

Verses 24-28 show again that whatever the believer has received of God might be used to edify the unbeliever.  Verses 29-33 also refer to the use of prophesying.  Each were to speak at one time so that all could learn and judge regarding what they heard. Whatever was spoken was to be “subject to the prophets”—the authority of God’s Holy Word. Verses 34-40 touch on the proper order and decency to be exercised for the spiritual growth of the entire church.