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

As others said, this makes compiler parsing your source code easier. But I would like to say a bit more: it can also make your source code more readable; consider this example:

if (if > 0) then then = 10 end if

The second "if" and the second "then" are variables, while others are not. I think this kind of code is not readable. :)