The behaviors of struggle, avoidance and anticipation plus the fact that it is only present in the presence of others (which is quite common) indicates that you probably have tonic stuttering, perhaps covert as well as you apparently change the words. To “fix” the problem. It depends on how you want to set it: -Either through fluency techniques like Erasm (where you just say the sound that makes you stutter in a low voice), or by speaking syllable by syllable or just by slowing down. -Either by just agreeing to block, even if I know it's not very pleasant, but that means not forcing more when blocking, or in your case not jumping or leaning forward, nor changing the words . Just accept that you have a blockage, let it exist, say what you want to say when it goes away on its own. Everything I say are just suggestions, and I am not able to make a diagnosis either. The only serious advice I can give you is to see a speech therapist, who can tell you what you have, and support you