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How do children produce speech?

HOW DO WE PRODUCE SPEECH?

Before we begin talking about how we produce speech, let's take a moment to find the following body parts on the image below:

  • Lungs (These are the 2 balloons of air in your chest)
  • Trachea (This is sometimes called the windpipe)
  • Larynx  (The Vocal Folds are located in the Larynx)
  • Pharynx (This is the back of the throat)
  • Nasal cavity (This is the back of the nose)
  • Oral cavity (This is the mouth)
  • Hard palate (This is the bony part on top of the inside of the mouth)
  • Soft palate (This is the soft part behind the hard palate)
  • Tongue and Teeth

 

THE BEGINNINGS OF SOUND…

Sound is made by moving air through our bodies.  Sound, or "phonation," is begun by bringing air up from our lungs through the trachea (our windpipe) and then bringing together the vocal folds, (which sit on top of the trachea).  Whether the vocal folds are open or not is what makes the difference between us simply breathing in and out and whether we make sounds as we breathe in and out. Are we just letting the air out silently from our lungs through our mouths or are we partly blocking that air in some way which will create noise?  The vocal folds are made up of muscular tissue which lies horizontally above the trachea and which can be opened wide or closed tight (and all of the movements in between).  When we bring air up from our lungs and our vocal folds are closed together, the air which flows through them makes them vibrate against each other, creating voice or phonation - the beginnings of speech.  Think of when you let the air out of a balloon and the noise that you hear as the air rushes through the small opening.  That sound is caused by the two edges of the balloon's opening vibrating against each other.  The same thing is happening with our vocal folds.

THE VOCAL FOLDS

When the vocal folds are open we can make what are called "voiceless sounds".  These sounds are made without phonation by simply using the air escaping from our lungs and changing the shape of our mouths as we breathe out the air. The difference between a voiced sound (one which involves the vocal folds being pressed together) and a voiceless sound (one which does not) can be understood by making the voiceless sound "sssssssssssss" out loud.  Now make the voiced sound "zzzzzzzzzzzzz".  Can you feel the difference?  Now try both sounds again while putting the palm of your hand against the front of your throat.  The vibrations that you feel when producing the "zzzzzzzzzzzzz" sound is that of your vocal folds vibrating against each other as the air passes through.  This is phonation.

ARTICULATION AND THE ORAL CAVITY

Once the air passes through our vocal folds it reaches either our oral or nasal cavity.  The oral cavity has a lot of influence over what kinds of sounds we produce, depending upon what kind of shapes we make with it.  This is referred to as articulation.  The different structures which make up the oral cavity and which help us to articulate are the upper and lower lips, the tongue, the jaw, the teeth and the roof of the mouth.  The roof of the mouth is divided into three different parts: the alveolar ridge, which is the bump behind your front teeth (this is where the tip of your tongue goes when you make the "d" sound in "dog"), the hard palate, which is the bony portion in the middle of the roof of your mouth (this is where the middle of the tongue hits the roof of your mouth to make the "y" sound in "yes"), and the soft palate or velum, which is the soft portion right at the back of your throat.  In order for your tongue to touch your velum, say aloud the word "go" and feel where the back of your tongue touches the roof of your mouth on the "g" sound.

NASAL SOUNDS

An interesting thing about the flow of air through our bodies is that it can split into two separate pathways after it passes through the vocal folds (this happens in an area above the trachea and larynx called the pharynx).  One of these pathways goes up through the nose (or nasal cavity), allowing air to escape, while the other passage exits through the oral cavity, allowing us to breathe out of our mouths.  This is how we can breathe out of either our nose or our mouth.  The velum, which we described in the last paragraph, is actually fairly soft and we can move or stretch it.  We can raise it up to stop any air escaping through our noses (we do this for most of the sounds that we make), or we can keep it lowered.  When we keep it lowered we make what are called "nasal sounds".  To understand this, make the sound "mmmmmmmmmmmmm".  Did you notice how the sound came out through your nasal passage rather than through your mouth?  This is a "nasal" sound.  There are only three nasal sounds in English: "m, n and ng".  All of the other sounds in English involve raising the velum to block off the air to the nasal passage.

TO RECAP:

The basis for sound is the movement of air through our bodies.  When the air is brought up from our lungs through our trachea it encounters the vocal folds.  Depending on whether the vocal folds are closed or open, phonation may or may not occur.  If the vocal folds are closed, phonation will occur, and we will produce "voiced" sounds (remember "zzzzzzz"); if they are open, no phonation will occur.  However, if we move around some of the structures in our oral cavity to articulate, we can produce "voiceless" sounds which don't require phonation at all (remember "ssssssss").  There are two ways for the air to escape:  one is through our oral cavity and the other is through our nasal cavity (remember "mmmmmm").  We can also use our tongues, lips, jaws and the different parts of the roof of the mouth to create different sounds. We can do all this as long as air is being brought up from our lungs and we have the strength and coordination to manipulate the many different parts involved.

It's amazing how much we take for granted in the process of speech.  Usually speech comes so naturally to us that we never have to think about it.  It becomes unconscious - like the act of breathing itself.  Hopefully this sheds a little light on some of the different processes and incredible synchronization involved in this complex communicative tool.

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