Switch-reference is like a super cool way that people who speak different languages can make sure everyone understands who is doing what. You know how sometimes when you talk to your friend, you might say "I went to the park and saw a dog, then I walked home", and your friend might say "She went to the park and saw a dog, then she walked home". It's a tiny bit confusing when your friend changes the word 'I' to 'she', right? It can make you wonder if they are talking about you doing those things or somebody else.
Well imagine if you spoke a language where it was really important that you always kept using the same word for 'I' or 'we' or 'you' or 'they' throughout your whole story! Imagine if you couldn't just switch to a different word halfway through. That could get really confusing!
That's where switch-reference comes in. Some languages have a way to show which person or group of people is doing the action, so that nobody gets confused. For example, instead of saying "I saw a dog and then I walked home", you might say "I saw a dog and then I walked home, and we were happy about it." The 'we' part is called the switch-reference, and it tells everyone listening that the same person who saw the dog is also happy about it.
So when people speak languages that use switch-reference, they can make sure nobody gets mixed up about who is doing what, and everyone can understand the story much better. Pretty cool, right?