With the heart, a man believes the Gospel and with our mouth confession is made unto salvation. This means that what you believe you speak. Work on a man's believe and what he says would change.
If you want to grow and speak more of God, then you need to hear more and believe more of God.

Jeremiah 9:23-24
King James Version
23 Thus saith the Lord, Let not the wise man glory in his wisdom, neither let the mighty man glory in his might, let not the rich man glory in his riches:

24 But let him that glorieth glory in this, that he understandeth and knoweth me, that I am the Lord which exercise lovingkindness, judgment, and righteousness, in the earth: for in these things I delight, saith the Lord.