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Human Speech System

The words we speak travel through air, carried by vibrations in the air. To create those air vibrations, we have an amazing speech system, which is much more than just our mouths.

Of course, we use air to breathe and live. But we also use air to speak and pronounce words, and that is what this page explains in very basic terms.


For every word that we speak, we can track the flow of air. It comes IN through our mouth/nose; it goes down our windpipe to our lungs. And then, to pronounce the word, it comes back up though our windpipe, and OUT through our mouth—and sometimes our nose.

As the air comes up from our (1) lungs, through our (2) voice box, and out through our (3) vocal tract—THAT is when we vibrate the air and change the "shape" of those vibrations to create different sounds, syllables and words.

Basic Human Speech System

1 Lungs

The lungs are two elastic sacs in the chest that draw in air (mainly to oxygenate the blood). To initiate speech, they push air back up through the windpipe towards the voice box.

2 Voice Box

As air rises up from the lungs through the voice box in the neck, it may or may not be vibrated (so-called voiced and unvoiced sounds).

vocal tract

3 Vocal Tract

To control and shape the air flow above the voice box, the air travels through and exits the vocal tract, which consists of:

  • the mouth (oral cavity)—tongue, teeth, lips
  • the nose (nasal cavity)

Using the vocal tract, we resonate the air and make two main types of speech sounds:

  • vowels
  • consonants

Speech Sounds

When we speak in English, we use about 44 different sounds. When we write in English, we use 26 letters (the alphabet A-Z). You notice that there are more sounds than letters, and so there are not enough letters to represent all the sounds. It's important to understand that when we talk about speech and pronunciation, we are talking about the sounds of the phonemic chart, NOT the letters of the alphabet.

1 Vowels

A vowel is a speech sound that we make by NOT blocking air as it travels out through the mouth.

example vowel sounds:
/ ɪ / i: / ʊ / u: / e / ɜ: / ə / ɔ: /

2 Consonants

A consonant is a speech sound that we make by blocking air as it travels out through the mouth or nose. We block air by touching together two or more of the lips, tongue, teeth, top of mouth and back of throat.

example consonant sounds:
/ p / f / θ / t / s / ʃ / ʧ / k /



A syllable is a meaningless unit of pronunciation having one vowel sound with or without surrounding consonant sounds, like this:

  consonant vowel consonant examples
  V   /aɪ/
  V C /ɒk/
C V   /tə/
C V C /pəs/


A word is a meaningful unit of speech formed from one or more syllables. For example, I is a one-syllable word and octopus is a three-syllable word, as you see in the examples below:

word number of syllables
I I 1
green green 1
quite quite 1
quiet qui-et 2
orange or-ange 2
table ta-ble 2
octopus oc-to-pus 3
interesting in-ter-est-ing 4
unrealistic un-rea-lis-tic 4
unexceptional un-ex-cep-tio-nal 5

One or more words can form a sentence.


  • The lungs push air up for speech.
  • In the voice box, air passing through can be voiced or unvoiced.
  • In the vocal tract, unblocked air makes vowels and blocked air makes consonants.
  • Vowels and consonants make syllables.
  • Syllables make words.
  • Words make sentences.

vibrate (verb): move fast and continuously backwards and forwards

vibration (noun): an example of vibrating

throat (noun): the passage that leads from the back of the mouth

windpipe (noun): the air passage from the throat to the lungs; the trachea

oxygenate (verb): charge or enrich with oxygen

oxygen (noun): a colourless gas in air that is essential for life

initiate (verb): cause a process to begin

meaningless (adjective): having no meaning or significance

meaningful (adjective): having meaning or significance

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