As you probably know, Emacs now has a C API that allows you to write extensions in C or any language that provides C bindings. Via Wilfred Hughes we have a pointer to this excellent documentation on how to use the system.
The documentation is fairly long and detailed. There are examples of how to use some of the functions and how to initialize your module. There’s no point in going over everything in this post so I’ll just refer you to the documentation if you’re interested. Be aware, though, that this API does not mean you can now write your extensions in C and not have to know anything about Lisp. Emacs is a Lisp machine and you will still have to understand general Lisp ideas and how data is represented so that you can communicate with it from your C (or other language) module.