The mouth consists of a caoutchouc cavity O, somewhat resembling the human mouth, and forming a continuation to the channel we have just described. The tongue C, likewise modelled on the human tongue, is placed within the mouth, and connected with two jointed rods _t_, _t_, fastened to its two opposite ends, so as to enable the tongue to raise its tip, or touch the palate, in obedience to the notes of the keyboard. The lower caoutchouc lip A can also be more or less closed, according to the action of the keyboard on its special rod. Finally, a circular metallic piece E, following the shape of the mouth, is placed above the upper lip, with a small opening in it to admit of the pronunciation of the letter _f_. The keyboard has fourteen notes, of different lengths, producing the following letters when lowered, _a_, _o_, _u_, _i_, _e_, _l_, _r_, _v_, _f_, _s_, _ch_, _b_, _d_, _g_. The longest corresponds to _g_, and the shortest to _a_. There are two pedals below the _g_ note and those of _b_ and _d_, corresponding with the opening of the tube which produces nasal sounds, and to the rod which regulates the opening of the larynx, and this makes it possible to obtain _p_, _t_, and _k_ from the notes _b_, _d_, _g_. The mechanical effects produced by lowering the different notes in succession are as follows:-- 1. The _a_ note moves the first five diaphragms. 2. _o_ also moves these five diaphragms, but varies the pitch, and closes the mouth a little. 3. _u_ does the same, only further closing the mouth. 4. _t_ moves a single diaphragm, raises the tip of the tongue, and opens the mouth more widely. 5. _e_ moves six diaphragms, throws the tongue further back, and opens the mouth still more. 6. _l_ moves five diaphragms, sends the tongue against the palate, and further opens the mouth. 7. _r_ moves six diaphragms and the tourniquet, lowers the tongue, and somewhat closes the mouth. 8. _v_ moves five diaphragms, almost closes the mouth, and keeps the tongue down. 9. _f_ lowers the circular appendix of the upper lip, and almost entirely closes the mouth. 10. _s_ moves three diaphragms, half closes the mouth, and half raises the tongue. 11. _ch_ moves three diaphragms, keeps the mouth half closed, and further lowers the tongue. 12. _b_ moves five diaphragms, closes the mouth, and keeps the tongue completely down. 13. _d_ moves six diaphragms, keeps the mouth three parts closed, and raises the tongue a little. 14. _g_ moves five diaphragms, keeps the mouth three parts closed, and the tongue completely down. _m_ is produced by lowering note _b_ and opening the valve of the pipe which gives nasal sounds. _n_ is obtained by lowering note _d_ and opening the same valve. _h_ is obtained from note _s_ by lowering the pedal which acts upon the larynx, and half closing it. Since the other letters of the alphabet are compound sounds, they can be produced by combinations of the preceding letters.