An international auxiliary language is like a secret code that people from all over the world can use to communicate with each other when they don't speak the same language. Imagine if you had a secret language that you and all your friends knew, and you could talk to anyone in the world who also knew that language. That's kind of what an international auxiliary language is.
You know how different countries have different languages, right? Like people in Spain speak Spanish, people in China speak Chinese, and so on. Well, it can be really hard for people from different countries to talk to each other if they don't know each other's language. That's where an international auxiliary language comes in.
An international auxiliary language is a language that's designed to be easy to learn and understand for people from all over the world. It's sort of like a mash-up of different languages, so it has words and rules that people from many different countries will recognize. That way, if people from two different countries meet each other and don't speak the same language, they can use the international auxiliary language to communicate.
There have been lots of different attempts to create an international auxiliary language over the years. Some have been more successful than others, but none of them have really caught on as the one language that everyone in the world speaks. However, there are still lots of people who think it would be really helpful to have an international auxiliary language, so they keep trying!