1 Corinthians 14:9-11 New English Translation (NET Bible)
9 It is the same for you. If you do not speak clearly with your tongue, how will anyone know what is being said? For you will be speaking into the air. 10 There are probably many kinds of languages in the world, and none is without meaning. 11 If then I do not know the meaning of a language, I will be a foreigner to the speaker and the speaker a foreigner to me.