Would you rather be able to only whisper, or only able to shout?

Have you ever heard of the game ‘bogies’? If you’re unfamiliar let me enlighten you. This classroom two-player classic consists of alternating saying the word ‘bogies’ getting successively louder, so you start off in the quietest whisper and the player who is bold enough shouts the dreaded word and wins.

Next time you’re in a quiet public place I dare you to have a go! Nevertheless, I digress. What is the use in being able to whisper and shout, and why are we the only animals which have developed talking, let along the other numerous noises we can make with our mouths?

The organ found in both humans and apes which is involved in sound creation is called the larynx, also known as the voice box. When humans evolved to be different to apes a number of things occurred. One of them being is that we developed longer necks, which have more room for our larynx. With a longer throat than our ancestors, the muscles here have more flexibility to move and therefore they are capable of making a larger range of noises in pitch or frequency. Frequency is how high or low the noise is, imagine a piano, at one end the noises created have a low pitch, whereas the other end has a higher pitch. These are each controlled by two flaps inside the larynx, just like blowing between two pieces of grass, they hit together to make a sound.

So this explains the range of noises we are able to make, but what about being able to shout and whisper. There are two main controls on what a noise is. These are the frequency (high/low), and the amplitude (loud/quiet). If you imagine every single combination of these two controls, you quickly see how many possibilities there are!

We use our lungs and diaphragm (muscle under the lungs) to control our breathing, exactly the same way that a bagpipe player uses his arm to control the air going from the sac to the tubes.

Test this out now. Puff out a breath of air really quickly …go on… and you’ll find the air comes out really quick at first, and then sort of flails off at the end? Now try breathing out the same amount of air over 10 seconds. You can almost feel the muscles in your chest controlling how much you breathe out. Breathing and being able to control the rate of breathing is vital for making controlled noise.

So how does this breathing turn into noise? When we talk or shout the flaps of tissue, our vocal chords, inside our larynx hit together. It’s just like when you pinch the opening of a balloon tight and make that annoying squeaky humming sound that probably annoyed your Mum a lot, the flaps of balloon are hitting together too, hence a squeak is made.

So knowing this, how do we whisper? Well it’s not really making a noise as such? Have you ever blown up a balloon and then let it loose; you know the runaway uncontrolled zig-zaggy flutter it makes through the air for about two seconds before it anti-climatically plops down to the floor? Well we can use this as an analogy for whispering. Little noise is made, the ends of the balloon are loose and don’t flap together. They let a lot of air out between them, and this is just what our vocal chords do when we whisper, completely separate. That’s why you use a lot more breath to whisper, more air is effectively being lost.

So with both shouting or whispering the balloon still lets air out. However it’s the articulation between the air coming from your lungs by tiny and fast vibrations of the balloon flap, or your vocal chords that create the sound you can hear.

The larynx and vocal chords aren’t alone in allowing you to talk, it’s a whole complex system of breath control, the shape of your mouth, the pressure of air you’re breathing out, what your tongue is doing and the shape of your throat.

And of course, the advantage of being able to control how noisy your voice is that you can convey emotion, communicate over long distances, assert dominance and, of course, play the game bogies!

There ya have it folks, which would you rather?