What is a language, really? It's not really an implementation (necessarily); a language can have multiple implementations, in which you have to ask "which one i

What is a language, really? It's not really an implementation (necessarily); a language can have multiple implementations, in which you have to ask "which one is the language?" if they have subtly different behaviour. In order to enforce what a language is, you can introduce a specification. This will say that "given a program X, the language will behave like Y". Now any implementation of the language can be checked for conformance. The spec itself might be some document, or perhaps just a "blessed" implementation ("the implementation is the spec").