i think in order to create your own programing lang you have to know deep knowledge about assembly lang . complier , assembler.
every programing lang first convert in assembly lang before machine code. so you can simple make a text editor , define some reserve words like in every programing lang , and after that make convert all your reserve words to respected assembly code and execute your code.
this is simple over view i know to create a programming lang is not this much easy but this will give a little bit idea how it works , if possible first study about compiler , assembler. and as thines01 said it totaly depend on your commitment . you can create simple commands of your own by doing this.