# C, 149 bytes, not tested

    #include <stdio.h>
    #include <unistd.h>
    #include <stdlib.h>
    int f(char *s){int n;while(*s){sleep(n=rand()%10+1);for(;*s&&n--;s++)printf("%.*s",1,s);}}

to run, add

    int main(){f("Programming Puzzles & CodeGolf");}
then compile and execute