1 Corinthians 14:9-11

New King James Version

⁹ So likewise you, unless you utter by the tongue words easy to understand, how will it be known what is spoken? For you will 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 ^[a]significance. ¹¹ Therefore, if I do not know the meaning of the language, I shall be a ^[b]foreigner to him who speaks, and he who speaks will be a foreigner to me.