1 Corinthians 14:9-11 World English Bible (WEB)
9 So also you, unless you uttered by the tongue words easy to understand, how would it be known what is spoken? For you would be speaking into the air. 10 There are, it may be, so many kinds of languages in the world, and none of them is without meaning. 11 If then I don’t know the meaning of the language, I would be to him who speaks a foreigner, and he who speaks would be a foreigner to me.