CONSONANTS
In speech, when the escaping breath stream meets with an obstruction formed by the tongue, lips, teeth, or velum (soft palate), the resulting sound is called a consonant. The word comes from the Latin, con and sonare, meaning with sound" or "to sound together.” The dictionary defines it as "an articulate sound characterized by friction, squeezing, or stopping of the breath in some part of the mouth. It is usually sounded with a more open sound called a vowel:. In other words, a consonant is formed when the vowel chamber is blocked either partially or wholly.
As there are many vowel sounds possible through adjustments of the articulatory organs, so also can many consonants be formed by making the blockage in different ways. Say slowly the following words, paying careful attention to the quality of consonants and the manner in which you produce them: to, do, pay, bee, key, go, lay, may, no, hang, red, vow, foe, see, rise, who, we, how, you, jug, chew, she, measure, thing, though. No doubt you noticed that, in order to pronounce some consonants, the column of air was at times completely stopped by the organs of speech and then released with a sudden explosion or puff; or sometimes it was only partially stopped, thus allowing the breath to escape gradually. When the current of air is completely stopped and then released suddenly, sounds produced are called stop consonants or explosives. They occur in the sounds t in to, d in do, p in pay, b in be, k in key, g in go, j in jug, and ch in chin. When the breath stream is only partly blocked, as in the sounds represented by r, 1, m, n, ng, th, f, v, s, z, y, sh, consonants called continuants are formed. Stop, or explosive consonants, are uttered quickly, but continuants may be lengthened or sounded continuously as the word implies.
In producing some consonants, the tip of the tongue obstructs the stream of breath; in others, the teeth and lips hinder the free emission of air, and sometimes the back of the tongue forms the blockage. Consonants articulated by the two lips (as p, b, m) are called bi-labial sounds; those formed by the lower lip against the upper teeth (as f, v) are known as labio-dental sounds. Those produced by the tip or blade of the tongue against the teeth or teeth-ridge (as t, d, n, th) are classified as dental sounds. Sounds articulated by the front of the tongue against the hard palate are termed palatal (as y), and those made by the back of the tongue against the soft palate (as k, g, and ng) are called velar sounds. In most sounds, breath escapes through the oral cavity or mouth. However, in n, and ng air is released through the nose. For this reason, these sounds are often called nasal or resonant consonants.