​Speaking In An Unknown Tongue

I Corinthians 14:12-17

12  Even so ye, forasmuch as ye are zealous of spiritual gifts, seek that ye may excel to the edifying of the church. 
13  Wherefore let him that speaketh in an unknown tongue pray that he may interpret. 
14  For if I pray in an unknown tongue, my spirit prayeth, but my understanding is unfruitful. 
15  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. 
16  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? 
17  For thou verily givest thanks well, but the other is not edified.