Voice is a sound produced in the throat by the passage of the air through the glottis, as it is expelled from the lungs. It is grave and strong in man, soft and higher in woman; it varies according to age, and is developed simultaneously with the larynx, as has already been stated. It is alike in both sexes in infancy, but is modified in youth; then the voice is said to "change." In the young woman it descends a note or two, and becomes stronger. In the young man the change is much more strongly marked. At the fourteenth or fifteenth year the voice loses its regularity, becomes harsh and unequal, the high notes cannot be sounded, while the grave ones make their appearance, and the masculine character of the voice is established. A year is generally sufficient for this change to be complete, and the voice of the child gives place to that of the man. Exercise of the voice in singing should be very moderate, if not entirely suspended, while this change is going on.
Voice is divided into singing and speaking voice. One differs from the other almost as much as noises do from musical sounds. In speaking, the sounds are too short to be easily appreciable, and are not separated by fixed and regular intervals, like those of singing; they are linked together generally by insensible transitions; they are not united by the fixed relations of the gamut, and can only be noted with difficulty. That it is the short duration of speaking sounds which distinguishes them from those of singing, is proved by this, that if we prolong the intonation of a syllable, or utter it like a note, the musical sound becomes evident. And if we pronounce all the syllables of a phrase in the same tone, the speaking voice closely resembles psalm-singing. Every one must have noticed this in hearing school-boys recite or read in a monotone, and the analogy is complete when the last two or three syllables are pronounced in a different tone. Spoken voice is moreover always a chant more or less marked, according to the individual and the sentiment which the words express. The accentuation peculiar to certain languages also gives the speech the character of a chant: to a French ear an Italian preacher seems always to sing. It is a chant also which is caused by all those inflections of the voice, which express our sentiments and our passions, and which vary with every thought. They extend from the feeble murmur, which the ear scarcely perceives, to the piercing cry of pain. Affectionate, sympathetic, imperious, or hostile, they sometimes charm, sometimes irritate, and always move us. It is related of Gretry, that he amused himself by noting as exactly as possible the "Bonjour, monsieur !" (Good day, sir!) of the persons who visited him; and these words expressed by their intonation, in fact, the most opposite sentiments, in spite of the constant identity of the literal sense. Baron, the comedian, moved his audience to tears by his recitation of the stanzas of the song, "Si le roi m'avait donne Paris sa grand'ville"—If the king had given me Paris his great city.