@Sidgis, eventually they will, but not necessarily immediately if they are well trained, according to Effects of the Elder Scrolls. If one is not prepared for the magnitude and trained properly to read a scroll then a novice would lose their sight immediately and it would never return. Those who regularly read the scrolls eventually go blind, which is the final price.
I was simply making the point that perhaps the dragonborn going mute could be a result of using the shouts, but perhaps not understanding them fully (physically performing them, but not understanding their spiritual significance.) Just a thought, is all.