1. THE HUMAN VOICE
- All of the vocal organs have other functions – breathing, sucking, chewing, swallowing.
- The lungs expand and contract to bring in air or let it out.
- Air expelled from the lungs travels up the trachea, or windpipe.
- At the top of the trachea is a structure of cartilage known as the larynx, or voicebox.
- The primary vibration needed for speech is produced in the larynx by the vocal cords.
- Above the larynx are three interconnected areas, the pharynx, the nasal cavity, and the mouth (or oral cavity) which serve as resonance chambers.
- The three together are called the vocal tract.
2. THE VOCAL CORDS
- Speech sounds produced while the vocal cords are vibrating are voiced;
- Those made without vibration are unvoiced, or voiceless.
- How can you tell if a speech sound is voiced or voiceless? There are three good tests.
- Take the sound [z] as at the end of the word buzz and the sound [s] as at the end of the word hiss.
- Make a long [z-z-z] and a long [s-s-s] as you apply the tests.
- Put your thumb and fingers on your throat, on each side of the Adam’s apple.
- Cover your ears with your hands while making the two sounds.
3. THE VOCAL TRACT
- Some speech sounds result from obstructing the flow of air somewhere in the pharynx or oral cavity.
- The obstruction may be partial, as in articulating the sounds [f v s z], or it may be complete, as in making the first and last sounds of pop, bob, tot, dead.
- Speech sounds which result from complete or partial obstruction are called obstruents’
- Other, more musical speech sounds are called sonorants, or resonants; examples are the vowel sounds of the four words above and the consonants of mill and run.
4. KINDS OF SPEECH SOUNDS
- Different kinds of speech sounds, different manners of articulating, are different ways of manipulating the air stream.
- We recognize SIX KINDS of speech sounds: vowels, glides, nasals, liquids, fricatives, and stops.
- Vowels and stops (the latter also called plosives) are completely different.
- Vowels are produced by allowing the air to flow freely, stops are made by complete obstruction of the air stream.
- Other kinds of speech sounds have some of the characteristics, or features, of vowels and some of the features of stops.
- Stops and vowels differ from each other in four features:
- A vowel is resonant, the result of periodic waves; when a vowel is articulated, particles of air vibrate in regular, repetitive patterns.
- A stop is essentially an instant of silence.
- To express this difference we say that vowels are [+ sonorant] and stops are [− sonorant].
- A vowel is the center or peak of its syllable, more prominent than what precedes or follows in the syllable.
- This distinction is captured with a feature [consonantal].
- When there is some interruption of the breath stream, as there is for stops, the segment is [+ consonantal]; Vowels are [− consonantal].
- The other four classes of speech sounds, fricatives, nasals, liquids, and glides, are partly like stops and vowels but of course are also different from them and from one another.
- The four features, [sonorant], [syllabic], [continuant] and [consonantal], describe their similarities and differences.
- Fricatives are segments like the [f v s z] of feel, veal, seal, zeal, respectively
- Nasals are segments like the [m] of mitt and the [n] of knit, sounds made by stopping the flow of air somewhere in the mouth but letting it exit through the nose.
Liquids include the [l] of lead and the [r] of read.
In their articulation the tongue is raised, partly impeding the flow of air, but the tongue is shaped in such a way that air flows around it, creating particular patterns of vibration.
Liquids are classed as [+ consonantal]; because of the periodic vibration they are [+ sonorant]; because air flows freely they are [+ continuant].
Finally, like nasals, they are Syllabic – usually not the peak of a syllable but sometimes the peak, as in metal and manner.
Glides include the [j] of yet and the [w] of wet, for example.
Glides are like vowels except in one feature.
A glide is like a vowel except that it does not have the prominence of a vowel, does not act as the peak of a syllable.
Glides, then, are [− syllabic] but in other respects are like vowels: [+ sonorant], [+ continuant], [− consonantal].
Four features have been used to define six classes of speech sounds. The following chart summarizes them, with abbreviations of the feature names that will be used hereafter:
