The natural gifts and the spiritual gifts are entirely separate.
A speaker may have a tremendous oratorical ability and may be able to stir the masses. But when it comes to the spiritually gifted, they are appointed by the Lord and only they can move the heart of the Blood-bought believer. The speaker may stutter or shuffle or lack training. The words may be simple. The power does not come from the ability, but from the speaker's availability as a lightening rod for the voice of God.
I have heard many fine singers. The most moving singing I have ever heard was by a man with multiple scleroses, bent and twisted in his wheel chair. He was difficult to understand. He sang "Victory in Jesus" and I was touched beyond words. Not because of his handicap, but because of the depth of his agreement with God.
Soldier of The Cross, shake loose from self-consciousness. Stop reviewing your service and words as though evaluating a performance.
He has asked you to be a living sacrifice, and as such, you may not lie on the altar holding up a mirror.
We move on. We welcome correction. We are servants of the Loving God. May He use us as He wills?
Tell Him.
Alone and aloud.