The truly wise person restrains his words, and the one who stays calm is discerning.
Wisdom has no need to grasp for truth with many words. It answers striking right to the heart, and hearts respond to it with great acceptance, or immediate and swift rejection. Unlike knowledge, wisdom comes with a temper shift.
"The fear of the Yahweh is the beginning of wisdom." (Psalm 111:10, Proverbs 9:10) One who speaks wisdom realises that the author of wisdom is in control, and appropriately places themselves under that perfect authority. That is where a calm spirit finds its anchor: in faith and trust in Yahshua.