Bible Verses About Public Prayer: Should not be made in an unknown language

For if I pray in a tongue, my spirit does pray, but my mind is unproductive.

So, what about it? I will pray with my spirit, but I will also pray with my mind; I will sing with my spirit, but I will also sing with my mind.

Otherwise, if you are giving thanks with your spirit, how will someone who has not yet received much instruction be able to say, “Amen,” when you have finished giving thanks, since he doesn’t know what you are saying?