1 Corinthians 14:9-11

Godbey(i) 9 Thus also if you through the tongue may give an indistinct word, how will that which is spoken be known? for you will be speaking into the air. 10 If it so happens that there are so many kinds of voices in the world, and nothing without a voice; 11 if then I do not understand the power of the voice, I will be a barbarian to the one speaking, and the one speaking will be a barbarian to me.