A computer takes instructions by 1s and 0s. Very roughly, in the electronic circuits there are a set series of questions that require a "yes" or "no" answer. Whether it's a 1 or a 0 will tell the computer what to do (1 being "yes" and 0 being "no"). To create a programming language, you basically just need to create something called a "compiler" that will translate a programming language you create to answer these preset questions (using sequences of 1s and 0s). Writing these requires lots knowledge of what kinds of questions the circuits are interested in and in what order they are asked. Thats basically it! Its a simple concept, but a difficult process. If this doesn't make sense, feel free to ask again and ask for me! Hopefully I can explain it better!