I think that this is one of those areas that would be greatly improved by starting students with assembly. It's fairly easy to grasp what each statement does in a small instruction set like MIPS since there aren't these sorts of preconceived ideas. Then once students have learned assembly, teachers can explain statements such as "X=X+1" unambiguously with the assembly instructions the students are familiar with.
I disagree about starting students on assembly. Assembly exposes all the implementation details on how we got computers to work efficiently, and exposes none of the theoretical basis for computation. Obviously you need to know both eventually, but to get started, I think it's a better idea to build on the mathematics students already know.
Say you want to print 2+2. In assembly, you have to put a two in two certain registers, then call add, then call a routine to convert the number 4 to the string "4\0", then find a file descriptor, then signal the OS that you want to make a system call (fwrite), ...
That is not a good way of teaching how computation works. The details in this case are arbitrary and irrelevant; there is no reason a computer has to distinguish between the string "4" and the result of adding 2 and 2.
