Why does a programming language need keywords?

Question

For example (in C):

int break = 1;
int for = 2;

Why will the compiler have any problems at all in deducing that break and fo

Answer 1

I guess it look very weird if not impossible to write the parser. E.g

int break = 1;
while (true) {
   // code to change break
   if (!break) break;   // not very readable code.
}