Depending on the air pressure, the whistle produces the sound of whispering, humming, storm, animal roar, up to the sound resembling a human scream. You can modulate the sound by covering and revealing the exit hole with your hand.
It can be used therapeutically for regression, recall of difficult experiences to release anxiety and tension. It can be also used to express respect for the dead, ancestors.
Due to respect for centuries-old traditions, please do not let the whistle become a tool to scare and hurt people. According to tradition, our breath has a great power, so when used with pure intention, it can bring a lot of good.
Here is a video which presents sound of such a whistle: