As I've written, there is a core written in C. The ratio of Emacs Lisp vs C is about 80/20. 20% might look rather large at first, but if you keep in mind that E

As I've written, there is a core written in C. The ratio of Emacs Lisp vs C is about 80/20. 20% might look rather large at first, but if you keep in mind that Emacs supports a large variety of operating systems (from MS-DOS(!) over Windows, OSX, Linux, *BSD to various other Unix flavors like AIX and Solaris), and also supports various toolkits (like Lucid/Athena and GTK), it actually isn't that much. Most of the C code works as a sort of hardware abstraction layer, providing a common interface to the Lisp layer for handling (bidirectional) display, processes, memory, and so on. Compared to that, the actual Lisp interpreter is tiny.