1 Corinthians 14:11-15

So if I do not know the meaning of the language, I will be unintelligible to the one who speaks, and the one who speaks will be unintelligible to me.

So you too, since you are eager to possess spiritual gifts, strive to excel for the edification of the church.

Therefore, one who speaks in a tongue is to pray that he may interpret.

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

What is the outcome then? I will pray with the spirit, but I will pray with the mind also; I will sing with the spirit, but I will sing with the mind also.