I am also a covert stutterer. It’s basically a person whose main objective in terms of fluency is to hide the fact that they stutter at all and the opposite of stuttering acceptance. This leads to communication avoidance on a lot of different levels, from switching words around before they come out to avoid blocks to avoiding speaking altogether etc. It can be a really painful way to live. Personally, I’m now in my late 30s and I am just now getting to the point where I can accept my stutter, in fact I almost want to stutter more freely and more often instead of living in fear of stuttering.