I'll second the use of Lisp as the implementation language. I've also used Prolog. For low level code, e.g. a virtual machine, you'll also need a low level

I'll second the use of Lisp as the implementation language. I've also used Prolog. For low level code, e.g. a virtual machine, you'll also need a low level language such as C or assembly language. If you're designing a language as a learning exercise, or a domain-specific one, my advice is to go right ahead, using a Lisp variant. If you don't know one, now is the time to learn one. If you're developing a general-purpose language, ask yourself how your language will be better than, or at least different to, every general purpose language in current use. Be ambitious. As languages belong to families (e.g. Algol variants, Lisp variants, functional languages, visual dataflow languages, etc.), you should aim for your language to be the best in its family. Your language should also be one you'd use yourself. I'm developing Full Metal Jacket (http://web.onetel.com/~hibou/fmj/FMJ.html http://web.onetel.com/~hibou/fmj/FMJ.html). It's very different from almost everything else, so I'm not expecting popularity overnight. The Dr Dobb's article is way too conventional for my requirements. My language doesn't require any parsing. Syntax, type, and memory errors can't happen. The ideal target machine would just run the code directly without any need for compilation, though I will at some point need to cross-compile it onto the von Neumann architecture, and for that dataflow analysis is unnecessary, making optimal object code simpler to generate. This is the direction I'd like to see computing go.