1 Corinthians 14:18

I thank my God, I speak with tongues more than ye all:

Paul possessed the gift of tongues abundantly, speaking with tongues more than all the others. Yet in the church he placed intelligible speech that teaches others far above unintelligible speech. He preferred a few understandable words by which he could teach and edify others to many thousands of words people cannot understand. All religious services are to be conducted to edify others and to work for the perfection of the church.

Speaking and praying must therefore be with both spirit and understanding, and be capable of interpretation. Otherwise the understanding is unfruitful, the unlearned cannot say Amen to the thanksgiving, and the hearer is not edified. The same principle applies to prayer and testimony and the social meeting, where speech in worship should be clear and understood so that it benefits the congregation. This requires a clear, cultivated voice consecrated to God rather than low, indistinct speech, so that what is said honors God and builds up His children.