Each form of resonance is particularly favored by certain vowels. _Oo_ and _oh_ lend themselves most readily to the acquirement of chest resonance. _Ee_ facilitates in bringing in nasal resonance, while _ah_ is the easiest vowel for obtaining command of the open throat and the forward tone, the most important functions of mouth-pharynx resonance. Two marked forms of faulty tone production often call for special means of correction. These are the throaty and the unpleasantly nasal tone. For the cure of throaty production relaxing exercises are generally used. Sighing and yawning on the vowel _ah_ with a free expiration furnish the basis of these exercises. Single tones and descending scale passages are practised in this manner, the breath being allowed to rush out freely and without control. Other directions are frequently given for the correction of throatiness. These include instruction in the support of the tone, the throat being relieved of pressure by a steady and controlled expiration. Bringing the tone forward in the mouth in the manner already described assists in this operation. An excessive or a faulty use of nasal resonance is looked upon as the cause of the unpleasantly nasal tone. Too great a degree of relaxation of the muscles of the soft palate may bring about this condition. The means most favored for the correction of this fault are, first, muscular exercise in raising and lowering the soft palate, which gives a better tonicity to these muscles; and, second, the imparting of the correct idea of nasal resonance in the manner already described. Another frequent fault of production, the tremolo, may result from any one of several causes. A lack of breath control may cause the expiratory pressure on the vocal cords to be unregulated and intermittent. Faulty methods of breathing, particularly those in which the upper chest is allowed to collapse at the start of the expiration, may lead to a flabby or ‘wobbly’ condition of the muscles which hold the larynx in place. A lack of support for the tone may result from the column of vocalized breath being directed backward, instead of toward its proper point of impact on the roof of the mouth. For the cure of the tremolo the teacher must analyze in each individual case and locate the seat of the trouble. When this has been pointed out the fault is eradicated by applying the appropriate instruction--controlling the breath properly, placing the tone in the correct position in the mouth, etc.