From my basic understanding of computer architecture, a computer understands instructions and a computer program written in a high level language is converted to a set of such instructions for the computer to understand.
Also, that given a set of rules are satisfied, any programming language can do what any other can do.
So why is it that a C program is faster than say a program in another language? Why is it not that regardless of the syntax, and features of the language, when converted to a set of instructions in binary, each programming language tries to get a similar result. Thus making each of them more or less as fast as the others, at the expense of say compilation time?
Obviously I'm missing something important here, so what is it?