Parallelization is like sharing your work with your friends to get it done faster.
Imagine you had to clean up a big room all by yourself - it would take a long time and be very tiring! But if you had some friends to help you, you could split up the work and get it done much faster.
That's what happens with parallelization. When a computer has a big task to do, it splits it up into smaller parts and each part is done at the same time by different parts of the computer. Just like how you and your friends can each clean a different part of the room at the same time.
This way, the computer can finish the task much faster than if it did it all by itself. It's like having a whole team of helpers!