So, you know how sometimes when you want to do something really important or special, like having a big party or starting a club with your friends, you might make a plan or a rule book called a "charter"?
Well, a long time ago, a group of really important people, called the kings and queens of England, made some really special rule books that they called "royal charters." These rule books were very important because they gave special powers or privileges to certain groups of people or places.
One of these places was Cornwall. Cornwall is a part of England that's way down in the south-west, right next to the ocean. It's a really special place with its own language, history, and traditions.
So, when the kings and queens of England made a royal charter for Cornwall, they were saying that Cornwall was a really important place that deserved special treatment. This royal charter made Cornwall its own separate area with its own laws and legal system, which meant that the people who lived in Cornwall were able to make decisions about their own lives and their own communities.
The royal charter also gave the people of Cornwall the right to be different from the rest of England, and to keep their own cultural traditions and language alive. So, even though Cornwall is a part of England, it has its own unique identity and history, and that's thanks in part to the royal charter.