If You Whisper, They'll Whisper
Have you ever noticed that when someone whispers, the people around them instinctively lower their voices too? This happens because we naturally mimic the behavior of those around us. If you're in a noisy environment and need people to quiet down, try speaking in a low voice or whispering.
The people around you will likely follow suit, bringing the overall noise level down. It's a great technique for teachers, parents, or anyone trying to maintain a quieter atmosphere.