tioned above. Consonants may accordingly be classified as they are
formed at the three places of interruption--lips, teeth, and fauces
respectively: (1) labial; (2) dental; (3) guttural.

The sounds formed at each of the places of interruption are divided into--
1. _Explosives_.--At one of the situations mentioned the resonator is
suddenly opened or closed during the expulsion of air--(_a_) without the
aid of voice, p, t, k; (_b_) with the aid of voice, b, d, g. When one of
these consonants begins a syllable, opening of the resonator is necessary,
e.g. pa; when it ends a syllable, closure is necessary, e.g. ap. No sharp
distinction is possible between p and b, t and d, and k and g if they are
whispered.

2. _Aspirates_.--The resonator is constricted at one of the points
mentioned so that the current of air either expired or inspired rushes
through a small slit. Here again we may form two classes: (_a_) without the
aid of the voice, f, s (sharp), ch, guttural; (_b_) with the aid of voice,
v, z, y. The consonants s and l are formed when the passage in front is
closed by elevation of the tongue against the upper dental arch so that the
air can only escape at the sides between the molar teeth: sh is formed by
the expulsion of the current of air through two narrow slits, viz. (1)
between the front of the tongue and the hard palate, the other between the
nearly closed teeth. If a space be left between the tip of the tongue and
the upper teeth two consonant sounds can be produced, one without the aid
of the voice--th (hard) as in that; the other with the aid of voice--th
(soft) as in thunder. Ch is a guttural produced near the front of the
mouth, e.g. in Christ, or near the back as in Bach.

3. _Resonants_.--In the production of the consonant m, and sometimes n, the
nasal resonator comes into play because the soft palate is not raised at
all and the sound waves produced in the larynx find a free passage through
the nose, while the mouth portion of the resonator is completely closed by
the lips. The sounds thus produced are very telling in the singing voice.

4. _Vibratory Sounds_.--There are three situations in which the consonant r
may be formed, but in the English language it is produced by the vibration
of the tip of the tongue in the constricted portion of the cavity of the
mouth, formed by the tongue and the teeth.

The consonants have been grouped by Hermann as follows:--

| |Labials.|Dentals.