THE VOICE AND SPEECH. 651 
tion of the vowels and consonants before a mirror, in order to 
acquire a practical knowledge of the relative share taken by 
the different parts of the supra-laryngeal vocal organs. Ordi- 
narily the tongue does, of course, function as the most impor- 
tant organ of speech; but the extent to which this organ, the 
front teeth, the lips, etc., can by practice be dispensed with is 
surprising in the extreme. Persons with more than half of the 
tongue removed manage to speak quite intelligibly. 
Consonants may be further classified according to the nature 
of the movements associated with their formation: thus, they 
may be either continuous or explosive, the meaning of which 
will be clear from the classification given below, and the basis 
of the latter from an inspection of the parts by a mirror dur- 
ing their formation, supplemented by consultation of our sen- 
sations at the time. 
The following tabulation may be of service, as representing 
at least certain aspects of the subject: 
Explosives: Labials, P, B. 
Dentals, T, D. 
Gutturals, K, G. 
Aspirates: Labials, F, V. 
Denials, L, 8, Sh, Th, Z. 
Gutturals, Ch (as in loch), Gh (as in laugh). 
Resonants: Labials, M. 
Dentals, N. 
Gutturals, N, G. 
Vibratory: Labial. 
Dental, R (common), 
Guttural, R (guttural). 
It is remarkable that certain consonantal (and vowel) sounds 
are wholly absent from some languages. All are familiar with 
the difficulty Europeans find in sounding the English th, as in 
thin. Their vocal organs fail to make the necessary co-ordina- 
tions, these not having been practised in youth. 
Pathological—Paralysis of the soft palate, giving rise to a 
nasal quality of voice, illustrates the importance of this little 
muscular curtain. 
Stammering is believed to be caused by long-continued 
spasm of the diaphragm—in other words, upon tonic contrac- 
tion of this muscle in the inspiratory position, usually depend- 
ent on some form of psychic excitement. Stuttering, on the 
other hand, is temporary inability to form the sounds desired; 
lack of co-ordination of parts principally. The various paraly- 
