1 Corinthians 14:9-11 New Revised Standard Version, Anglicised (NRSVA)
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. 11 If then I do not know the meaning of a sound, I will be a foreigner to the speaker and the speaker a foreigner to me.