7.2.1 The Vocal Organs

Sound is produced by the rapid movement of air. Most sounds in human spoken languages are produced by expelling air from the lungs through the windpipe (technically the trachea) and then out the mouth or nose. As it passes through the trachea,

the air passes through the larynx, commonly known as the Adam's apple or voice-box. The larynx contains two small folds of muscle, the vocal folds (often referred to non-technically as the vocal cords) which can be moved together or apart. The space between these two folds is called the glottis. If the folds are close together (but not tightly closed), they will vibrate as air passes through them; if they are far apart, they won't vibrate. Sounds made with the vocal folds together and vibrating are called voiced; sounds made without this vocal cord vibration are called unvoiced or voiceless. Voiced sounds include [b], [d], [g], [v], [z], and all the English vowels, among others. Unvoiced sounds include [p], [t], [k], [f], [s], and others.

The area above the trachea is called the vocal tract, and consists of the oral tract and the nasal tract. After the air leaves the trachea, it can exit the body through the

mouth or the nose. Most sounds are made by air passing through the mouth. Sounds made by air passing through the nose are called nasal sounds; nasal sounds use both the oral and nasal tracts as resonating cavities; English nasal sounds include m, and n, and ng.

Phones are divided into two main classes: consonants and vowels. Both kinds of sounds are formed by the motion of air through the mouth, throat or nose. Consonants are made by restricting or blocking the airflow in some way, and may be voiced or unvoiced. Vowels have less obstruction, are usually voiced, and are generally louder and longer-lasting than consonants. The technical use of these terms is much like the common usage; [p], [b], [t], [d], [k], [g], [f], [v], [s], [z], [r], [l], etc., are consonants; [aa], [ae], [ao], [ih], [aw], [ow], [uw], etc., are vowels. Semivowels (such as [y] and [w]) have some of the properties of both; they are voiced like vowels, but they are short and less syllabic like consonants.