A whistle can hail a taxi, make a boring task feel shorter or show support for a favorite team. However, trying to deliver an ear-piercing tweet and coming out with a dry hiss can be a humiliating experience. To get the most out of your whistle, you'll need to master and practice some basic techniques.

Simple Whistling

In 1944's To Have and Have Not, Lauren Bacall memorably summarizes the basic whistle by saying: "You just put your lips together and blow." To perform a basic whistle, begin by lightly wetting your lips. Pucker them as if you were making an "oo" sound, and then blow air out between them. You can vary the note of your whistle by moving your tongue inside your mouth. After you've produced a note by whistling, experiment with additional techniques. Change the position of your lips to vary the sound you're making, pump more or less air from your diaphragm to vary your volume or flutter your tongue to give your whistle a vibrato effect.

The Two-Finger Whistle

The two-finger whistle is the classic taxi-hailer, an ear-splitting squeal that draws attention from everyone in a wide area. Although whistles vary, this technique is typically the loudest, capable of producing sounds of more than 130 decibels.

Using both hands, touch the tips of your index fingers together to form a triangle. Alternatively, use both your index and middle fingers. You can also use the thumb and index finger of one hand, held together in a circle -- imagine the hand gesture for "OK."

Wet your lips and tuck them in to cover your teeth. Place your fingers firmly in your mouth, underneath the tip of your tongue so that they push it slightly up and back. Close your mouth firmly to form a tight seal, and then force air out through the gap.

This technique is a tricky one, and you probably won't produce a whistle on your first try. Vary your finger placement and tongue position slightly until you find the two-finger whistle that's right for you.

Using a Blade of Grass

A playground classic, the grass-blade whistle uses the same principle that gives woodwind instruments like the clarinet or saxophone their voices. Pluck a blade of grass, the wider the better; alternatively, you can use a strip of paper. Hold your hands parallel to each other, pressing the blade vertically between your thumbs with its edge toward you. A short length of the grass should be visible in the curve between the ball and tip of your thumbs, with a slight gap on either side of it. Stretch the grass as tightly as possible.

Hold the grass to your lips, purse them tightly and blow. The air will cause the grass blade to vibrate, making a sound that varies from a deep buzz to a high-pitched honk. Like finger whistling, this is a tricky technique that can take a little practice to get right. If you're struggling to get a sound out of the blade, make sure it's stretched tightly by pressing the tips of your thumbs together and pushing them upward.

Between the Teeth

Also called roof whistling or palate whistling, whistling between your teeth is somewhat different from other forms of whistling. Don't purse your lips; instead, open your mouth widely but narrowly, stretching it as if smiling. Raise your tongue until it is behind your front teeth, almost but not quite touching the roof of your mouth.

Blow air out of your mouth; the narrow opening between your tongue and palate should create a whistle, much like the narrow opening of a puckered mouth. You can vary the sound of this whistle by shifting your tongue, opening or closing your mouth slightly or just moving your lips.

Improving Your Whistling