How are Speech Sounds Made?
English uses air set in motion from the lungs, a Pulmonic Egressive Airstream.
If the vocal cords are apart, the air has a relatively free passage into the mouth. If, on the other hand, the vocal cords are adjusted so that the passage is narrowed, the air passing through causes them to vibrate. Sounds produced when the cords are vibrating are said to be voiced, while the sounds produced when they are apart are said to be voiceless. If the vocal chords are closed tightly, we can produce something called a glottal stop. Think of the Cockney pronunciation of the /t/ in 'butter'. Try to say it, can you feel the stoppage of air?
In Normal English, the vowel sounds, and many of the consonant sounds are voiced. Try saying a long zzzz, buzzing like a bee. If you put your hands over your ears, or on your Adam's apple, you should be able to detect the vibration. Then try a long ssss. This time you should not feel any vibration. Although both /s/ and /z/ are produced in the same way, we can now say that /z/ is voiced and /s/ is voiceless.
In speech production, the major difference in production is between consonants and vowels.
The air passages about the larynx (voicebox) are known as the vocal tract.
The parts of the vocal tract used to form sounds are called articulators.
We will start by looking at how consonants are produced.