The Khmer language is a way that people in Cambodia talk to each other. Just like how you might speak English with your family and friends, people in Cambodia use Khmer to communicate.
Khmer has its own way of writing with special letters called "script". It might look different than the letters you know, but just like how you learn to write your ABCs, people in Cambodia learn to write in Khmer script.
Khmer is also a tonal language, which means the tone (or pitch) of your voice can change the meaning of a word. This might sound tricky, but it's like how when you say "I" it doesn't sound the same as "eye". In Khmer, there are different tones for different words, which makes it important to pay attention to how you say something.
People who speak Khmer might sound different from people who speak English. They might have different words for things and use different grammar. But just like how you can learn to speak different languages, people can learn to speak Khmer too. Learning another language can help us understand and communicate with people from different cultures and places.