I. Labial or lip sounds, which may be sub-divided into
- a) bi-labial sounds, viz. sounds articulated by the two lips: examples p, m, w, and
- b) labio-dental sounds, viz. sounds articulated by the lower lip against the upper teeth: example f.
II. Dental sounds, viz. sounds articulated by the tip or blade (§ 33) of the tongue against the 'upper teeth or teeth-ridge ($ 31). It is often convenient to sub divide these into two classes
- a) pre-dental sounds, viz. sounds articulated by the tip or blade of the tongue against the teeth: example θ, French t.
- b) post-dental, or alveolar, sounds, viz. sounds articulated by the tip or blade of the tongue against the teeth-ridge: examples z, ʃ, the English t.
III. Palatal sounds, viz. sounds articulated by the front of the tongue (§ 33) against the hard palate: example j.
IV. Velar sounds, viz. sounds articulated by the back of the tongue against the soft palate: examples k, ŋ.
V. Uvular sounds, viz. sounds articulated by the back of the tongue and the extremity of the soft palate or the uvula: example ʀ (§ 260).
VI. Glottal or laryngal sounds, viz. sounds articulated in the glottis: example ʔ (§ 160).
65. If we classify consonants according to the manner in which the organs articulate them, we distinguish six main classes.
I. Plosive consonants, formed by completely closing the air passage and suddenly removing the obstacle, so that the air escapes making an explosive sound: examples p, d, g. These sounds are called stops by many writers.
II. Nasal consonants, formed by completely closing the mouth at some point, the soft palate remaining lowered so that the air is free to pass out through the nose: examples m, n. (The nasal consonants are the only English sounds in which the soft palate is lowered.)
III. Lateral consonants, formed by an obstacle placed in the middle of the mouth, the air being free to escape at the sides (see, however, § 234): example l. These sounds are sometimes called divided consonants or side consonants.
IV. Rolled consonants, formed by a rapid succession of taps of some elastic organ: example rolled r. These sounds are often called trilled consonants.
V. Fricative consonants, formed by narrowing the air passage at some point so that the air escapes making a kind of hissing sound: examples f, z.
VI. Semivowels, or vowels used in the capacity of consonants (see § 58): example w.
66. It is sometimes convenient to group the nasal, lateral and rolled consonants together under the name of liquids.
