How do you write your own programming language from scratch?

Writing your own programming language is an incredibly ambitious, and almost unachievable, goal. You won't be able to do this on your own unless you are a hardworking genius. Writing a programming language entails making a way for the average individual to communicate with electronic equipment. To make a language you need a working knowledge of the electronics you are making the language for - either a CPU or a smaller chip.

When you understand how all the 1s and 0s (off and on, respectively) work, then you can combine them to create definitions for different programming Words (i.e. Add, Subtract, If/Then, etc.).

An alternative is to base your programming language off another programming language. In other Words, if you would like to simplify a language like C then you would need a working knowledge of that language. From that knowledge, you can create definitions which can be used to invoke C code.

There are programs to create compilers -- YACC is the most well known of them (use google for details).