Imagine you have a friend who is new to computing. He is not necessarily interested in going into programming, but he would like to know the basics in terms of how computers work, how programs are written, and how computers communicate with each other. You are talking to him about the basics, but he keeps confusing operating systems, programming language, computer language, and markup language. How would you use very plain language to explain to him the differences between these things and how they interact with each other?