As sklogic said, no need to learn Racket:

It has multiple Lipsy dialects: http://docs.racket-lang.org/guide/dialects.html

And a datalog one: http://docs.racket-lang.org/datalog/index.html

It knows C: http://pkg-build.racket-lang.org/doc/c/index.html

And Javascript: https://github.com/lwhjp/ecmascript

And Algol: http://docs.racket-lang.org/algol60/index.html

And Pascal: https://github.com/soegaard/minipascal

It shouldn't be too difficult to teach it Lua ;).

No need to learn Racket, it's easy to build any language on top of it. Having a single meta-language as a base allows diversity and choice for end users that is not possible with any of the inferior (non-meta) languages.