1 Corinthians 14:8-10

New Revised Standard Version, Anglicised

⁸ And if the bugle gives an indistinct sound, who will get ready for battle? ⁹ So with yourselves; if in a tongue you utter speech that is not intelligible, how will anyone know what is being said? For you will be speaking into the air. ¹⁰ There are doubtless many different kinds of sounds in the world, and nothing is without sound.