That’s the old way of language design; used to be that to create a “programming language”, you’d write a spec and call it a day. That just doesn’t fly anymore. These days, you actually have to implement a parser and compiler, and not only that, you have to write the entire standard library as well, along with a toolchain complete with debugger, profiler, package manager, language server implementation, etc.

All this is to say that a programming language these days is really the sum of its parts, not a spec.