What makes D, D?

[Dimitar Kolev]

Hello my questio is:

What makes D, D?

For example:

There are more than one compiler for D, so what makes that interpretation of D, D?

Didn't the implementers of that compiler change and add additional features to the language?

Maybe I am missing the point, so please elaborate in either case.

I am new to the D community (hope this is suficient as an excuse for my lack of knowledge :)).