How Do We Speak?
9xb Harrogate
To most of us - thankfully unburdened by medical conditions such as MS - speech seems as easy and as natural as breathing. We think something and then say it. Sometimes, we even speak before thinking with hilarious/disastrous consequences. But the actual physical act of speaking itself is surprisingly complicated - involving several muscles, body parts and mechanisms. Thoughts into Speech Behind the act of speech lies thought. This is still poorly understood, but involves the firing of electrical signals between the millions of synapses within the brain to form patterns and connections that somehow comprise "thought." With near simultaneity, the brain also fires signals to the parts of the body concerned with speaking and delivers instructions to convert these into speech. This includes all the varieties of tone, pitch and emphasis that might be included in whatever you're saying. That all this happens subconsciously practically in time with the action of thought itself is something of a minor miracle. The next time you leave an argument and only then think of the ultimate riposte, go easy on yourself: after all, you've turned millions of minute electrical signals into comprehensible sound without giving it a second thought. In many ways, it's the neatest trick in all of human evolution and without it we'd probably still be living in the trees, cowering from the monkeys. Like all sound, speech depends on 'waves' delivered through a 'medium'. Or, if you prefer, disturbances in the air (speech underwater being mainly limited to "help!"). Vibrations in the air are decoded by your ears to make them into recognisable sounds. Another amazing feat, when you consider it. The signals sent by your brain cause your mouth to open, your tongue to move, your lungs to inhale/exhale and your vocal chords to shorten or lengthen with amazing synchronicity and ultimately verbalise your thoughts. The action of all these elements with the air in your mouth causes the molecules in the air to vibrate. These vibrations are carried outward in the form of waves, which are then received as 'sound' by the ear of the lucky recipient. The lungs - push air up the larynx as the diaphragm (itself a large muscle that sits below the lungs) is contracted The larynx - comprises two thin membranes which are contracted or relaxed by various muscles. This creates a vibration in the air that actually forms the basis of the sound of speech. The tighter these are contracted, the higher the frequency with which they vibrate and therefore the higher the pitch of our speech The throat, mouth and nasal cavity - adjust the 'tone' of the sound through changing shapes The lips, tongue and jaw - create the various sounds of vowels and consonants that actually articulate the words