1 Corinthians 14:8-10

King James Version

⁸ For if the trumpet give an uncertain sound, who shall prepare himself to the battle?

⁹ So likewise ye, except ye utter by the tongue words easy to be understood, how shall it be known what is spoken? for ye shall speak into the air.

¹⁰ There are, it may be, so many kinds of voices in the world, and none of them is without signification.