1 Corinthians 14:7-8; 1 Corinthians 14:10-11

7 And even things without life giving sound, whether pipe or harp, except they give a distinction in the sounds, how shall it be known what is piped or harped ? 8 For if the trumpet give an uncertain sound, who shall prepare himself to the battle?
10 There are , it may be , so many kinds of voices in the world, and none of them is without signification . 11 Therefore if I know not the meaning of the voice, I shall be unto him that speaketh a barbarian, and he that speaketh shall be a barbarian unto me.