What language do they build other languages with?

Question

What language is used to build low level languages like c++ and java?

How could you build the first language with no language?

Answer 1

I think the key insight to your question is the notion of boot-strapping. The link will describe how a language can self-host.

It is relatively common in the Lisp community. e.g. Some university classes will use Scheme to write a language subset (this is not a compiler class activity).

That said, many compilers are written in other languages. For example, PUGS (Perl 6) is written in Haskell. Ruby is available in C or Java (as JRuby).