Okay little one, imagine you have a best friend who speaks a different language than you. They are from a country called Macedonia and they speak Macedonian. Now, you want to make sure that your friend feels welcome and included when they come to your house to play. So, you learn a few words in Macedonian like "hello" and "thank you" so you can make them feel special. This is called being a good friend and being considerate of others.
But in history, some people didn't act like good friends. Instead, they wanted everyone to be just like them and they didn't care about other people's languages or cultures. So, they would force people who spoke different languages to give up their own language and culture and adopt the language and culture of the rulers. This is called "macedonianisation."
For example, long ago, there were some countries that wanted to take control of Macedonia and make everyone there speak their own language instead of Macedonian. They did this by not allowing Macedonian language or culture to be taught in schools, making it hard for Macedonians to get jobs and treating them unfairly. This made it very difficult for Macedonians to keep their own language and culture.
In conclusion, Macedonianisation is when people are forced to give up their own language and culture and adopt the language and culture of those in power. We should always try to be good friends and respect each other's differences.