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. |Gutturals.| |1. Explosives-- | | | | |a. Without the voice|P |T |K | |b. With the voice |B |D |G | |2. Aspirates-- | | | | |a. Without the voice|F |S (hard), L, Sh,|Ch | | | |Th (hard) | | |b. With the voice |V |Z, L, Th, Zh |Y in yes | | | |(soft) | | |3. Resonants |M |N |N (nasal) | |4. Vibratory sounds|Labial R|Lingual R |Guttural R| H is the sound produced in the larynx by the quick rushing of the air through the widely opened glottis. Hermann's classification which I have given is especially valuable as regards the speaking voice, but Aikin classifies the consonants from the singing point of view, according to the more or less complete closure of the resonator. CLASSIFICATION OF CONSONANTS (AIKIN)