As the vowels are differently formed in different languages, so is it also with the consonants. The North Germans form the letter _r_ with the soft palate, which is made to vibrate by the exhalation of the breath. The South Germans, Russians and Italians form the _r_ by the vibration of the tip of the tongue. It is only this mode of forming the _r_ which is to be used in singing, and must be learned by those who do not usually form it thus. This is sometimes rather difficult, but it can be done by repeating frequently and rapidly, one after the other, the syllables _hede_, _hedo_, or _ede_, _edo_. In this way the tongue gets accustomed to the right position and motion, which it by-and-by learns rapidly enough for the formation of the rolling _r_.
The Italians, likewise, form the _l_ with the tip of the tongue, the Germans and English mostly with the side edges of the tongue. With some attention one can, by feeling, find out in his own organ the place for the formation of the different vowels and consonants, and an ear accustomed to delicate differences of tone will perceive the right place in others.
But in teaching, the example of the wagoners must be followed, and as these people have found out the most appropriate vowels and syllables whereby to make themselves understood by their animals, we must choose what is best fitting to the formation of tone in singing.
Long before I found the scientific reason of this mode of proceeding, my attention was called by Frederic Wiek, in Dresden, to the fact that a fine tone can be most quickly attained by practising in the beginning upon the syllables _sü_, _soo_, or _dü_, _doo_, and by not passing to the other vowels until one is accustomed to produce tones in the front of the mouth. These syllables are naturally spoken by the Germans and the English in the front part of the mouth. The _s_ is formed with the lips apart, while the air is blown through the upper teeth; it thus assists one, united with _u_ (_oo_), to direct the tone forwards. But because in the _u_ the lips are almost closed, care must be taken that, within the lips, the teeth are far enough apart. The cavity of the mouth must be large enough to allow of the largest possible wave of sound, since upon the size of that, as we know, the strength of the tone depends. When the pupil, after some practice, has learned to give the right direction to the stream of sound, he must be required gradually to form the other vowels like the _soo_ in the front part of the mouth, passing from this syllable immediately to the other vowels, as, for example, _soo-a_, _soo-o_, _soo-e_, _soo-o-e-ah_, &c. Only care must be taken that the course of the air preserves its right direction.