How to defend myself?

How to defend myself? Hey! I’m 16 yrs old and i have a stutter, you might say its severe, and this year was a big change for me, i accepted myself that its a part of me and now i don’t have a problem with public speaking, but when i’m in an argument, and the other guy/woman, won’t give me a chance to defend myself, what do i do? How do i win an argument or a fight or anything without someone feeling pity? Btw, I’m new to this subreddit and i’m happy to be hear