language creation

Is it possible to write a programming language with an existing one?  I want to create a game creation program, and have it use it's own language for additional programming.  Something similar to Game Maker.

I've recently just wrote something like this; as i decided that lua/xml was probably too hard for the graphicians and the designer.. anyway; try to make it as simple as you can. (did this in C++ btw, not too familiar with C)

Anyway, if you're gonna go ahead and make your own language: i suggest you start by simple loading a file into a large char string, and the parse it up piece by piece, looking for spaces.
Then simply start looking through your parsed char variables, looking for commands.

Good luck guy..