Phonetics and Phonology

The topic of speech production examines the processes by which humans convert hnguistic messages into speeeh. The converse process, whereby humans determine the message from the speech is called speech perception. Together these form the backbone of the field know as phonetics. In 

In addition to the fundamental frequency, a periodic signal usually has energy at other fi e- 

Sounds such as [s], [f] and all vowels can be spoken as a continuous sound, and are therefore called continuants. By contrast stops are sounds which have a relatively short duration which can only be spoken as events and can not be spoke continuously. The [p] sound in pen or [t] sound in TIN are stops. Stops are produced by creating a closure somewhere in the vocal tract so that all air flow is blocked. This causes a build up of pressure, followed by a release where the air suddenly escapes. Because the sound is produced in this way, the sound must have a finite, relatively short duration and hence these sounds caimot be produced continuously. 

For most speech sounds, the acoustic signal leaves via the mouth - such sounds are termed oral. For a few however, the sound leaves via the nose such sounds are called nasal. In English the first 

The velum is a piece of skin at the back of the mouth. When it is raised, the nasal cavity is blocked off and the speech is completely oral. When the velum is lowered, the sound will be nasal or nasalised, depending on if the mouth is closed or open. It is important to note that in an oral 

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Clark, J., and Yallop, C. An Introduction to Phonetics and Phonology. Basil Black-well, 1990. 

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