I think even if you are hiding the actual stuttering, there is still mental aspects of stuttering going on inside of you, such as holding yourself back from expressing yourself. You may have developed a stutter because of a fear of expressing yourself, or in other words, you feel unsafe to be you in all situations. And you repress emotions such as the feeling of being assertive. While you speak your speech is being canceled out due to two opposing forces: the desire to speak vs. the desire to not be criticized OR a fear of being overwhelmed by any rewards you receive from whatever you say when you speak. I would highly recommend the book Redefining Stuttering by John Harrison. You asked a good question about whether or not you are stuttering if you hide it. Go to page 346 to a really good, in depth answer to your question. Here is a free link I found to the book https://www.mnsu.edu/comdis/kuster/Infostuttering/Harrison/redefining-stuttering.pdf