Imagine two people trying to have a conversation, but one is talking really fast while the other is super slow. That's kind of like asynchronous communication. Asynchronous events are things that don't happen at the same time or at the same speed. Emails and text messages are asynchronous communication examples - you can send a message, and the other person can respond whenever they're available. This is different from synchronous communication, like a live chat or phone call, where both parties need to be available at the same time.
