How come you can still talk and walk even when you lose your memory?

Different parts of your brain store different things. When you lose your memory the part of yoru brain working that part may nto work properlly but the part that runs routine procedures in your brain will funciton normally.

I not sure of the exact reason but I do know that your brain works in sections. I think the part of the brain that holds that type of memory like walking and talking is different from info like names and locations, I', sure there have been cases when people have forgotten how to talk properly or even forgotten words but when it comes down to movement, that is muscle memory. your body remembers how to do that naturally, it's not really something you remember to do everyday.

walking and talking are bodily manipulations, not necessarily a part of one's memory

No.