Yelang was a place a long time ago, kind of like a city, but it wasn't like the cities we have today. It was in China, and it was a very special place. In Yelang, people spoke a language that was different from the language that most people in China spoke. It was like they had their own secret code!
They also had different customs and ways of doing things. They had special ways of making clothes and food, and they even had their own money!
Even though Yelang was very special, it didn't last forever. Eventually, the people who lived there had to leave and go live somewhere else. But even today, people still talk about Yelang and how important it was.