Hi there! I am a speech therapist and I stutter. It sounds like what you are describing are secondary characteristics. These are physical or learned responses developed to cope with and avoid moments of stuttering. These include escape behaviors, like eye blinks or head nods (or foot taps) used to terminate a stutter, and avoidance behaviors, such as word substitutions or using filler words to prevent stuttering. These behaviors can become ingrained habits, contributing to the overall struggle and frustration of stuttering. I also used to tap my hand on my leg. They can often be distracting for listeners because it takes attention away from the message you are trying to communicate. In speech therapy, we work to reduce secondary behaviors by using techniques such as desensitization to reduce the discomfort, fear, or anxiety associated with stuttering. Additionally, therapy often involves addressing the underlying emotions and attitudes towards stuttering, helping individuals to stutter in an easier way that is less disruptive to communication. Here is a longer article about it if you're interested: https://stutteringtherapyresources.com/blogs/blog/even-more-thoughts-about-secondary-characteristics