Articulatory Phonetics 101: The Vocal Tract

This is Part 1 of a series covering the basics of articulatory phonetics, the study of how humans physically produce speech sounds. For the full list of posts, see the Articulatory Phonetics 101 Index.

Have you ever wondered how your body physically produces speech? When you think of something to say, how does your body create the sounds that we recognise as words?

That’s what we’re going to look at in this video.

Breath Control

The physical production of a speech sound begins with an intake of breath.

What happens when you breathe in is that your diaphragm contracts. This increases the volume of your lungs, which reduces the air pressure in your lungs. As a result, air rushes into your lungs to occupy the low-pressure space there and equalise the air pressure.

As you release your breath, your diaphragm relaxes, reducing the volume of your lungs and increasing the air pressure, pushing air out of your lungs.

The air leaving your lungs passes through an array of organs that shape and alter the flow of the air, which we call the vocal tract.

The Vocal Tract

The air comes up through the trachea, and moves past or through the organs of the vocal tract in this order (more or less):

  • glottis
  • epiglottis
  • pharynx
  • uvula
  • velum
  • tongue (usually divided into four sections: root, body, blade, tip)
  • hard palate
  • alveolar ridge
  • teeth
  • lips

What happens when we speak is that we alter the shape of the vocal tract. All human speech is created by manipulating airflow through the vocal tract, using the parts of the vocal tract that are able to move (primarily the tongue, lower jaw and lips). We’ll look at these different parts of the vocal tract and these movements in more detail in future videos.