Writing down words, typing them, has really helped me say things out loud.
Writing has broadened my vocabulary and like doing scales helps improve ones music, writing has strengthened my communication abilities.
Those solid words, sometimes spurting out in rivulets, other times squeezed out in pebbles, give the words spoken into the air more shape. The audible ones are uttered with more confidence and chosen with more care.
Words always used to trip me up, hold me back, create nets in which I would get tangled, and block communication. Words would shroud me in heavy cloth that muted my real intent.
By allowing myself permission to write through mistakes and sift through what's left, I'm also allowing myself to talk in the ways I want to, not out of fear or for purposes of crowd control or to manage my audience, but to speak, to communicate, to represent myself.