Okay kiddo, let me explain "one person, one language" in a way that's easy to understand.
Every person in the world speaks at least one language, right? Well, "one person, one language" means that each person should try to learn and use just one language at a time.
For example, let's say you speak English and you wanted to learn Spanish. That's great! The idea behind "one person, one language" is that you should focus on learning Spanish and using it as much as possible, instead of trying to learn Spanish, French, German, and Chinese all at the same time.
By focusing on just one language at a time, you can really improve your skills and become more fluent. It's like practicing soccer - if you try to learn too many new skills all at once, you might not perform as well. But if you focus on just one skill and practice it a lot, you'll get really good at it.
So, "one person, one language" is all about taking it one step at a time when it comes to learning new languages. By focusing on one language at a time, you can become a better communicator and have fun learning a new skill!