Grunting is a noise which is produced when, after the larynx has been perfectly closed, whether spasmodically or as a voluntary action with the object of holding the breath, the current of air thus interrupted is suddenly resumed. In the grunt we must distinguish two elements: the first is a clicking sound, and the other an explosive sound or slight report. The click is the noise produced by the meeting of air in the space left vacant when two moistened bodies are suddenly separated. It forms, however, but a very small part of the noise of grunting, and can scarcely be experimentally demonstrated. The "report" is the well-known phenomenon connected with the sudden expansion of a body of compressed air.
"Talking through the nose" when a person has a cold is in reality talking with the nose so stopped that less rather than more than the usual quantity of vibrating air can pass through the nasal cavity. In producing certain articulate sounds—those which occur in English are represented by m, n, and ng—all the vocal air escapes from the pharynx by the nose. The nasal air-passage has the general form of a resonator, and there can be no doubt but that it has a corresponding influence, and that the sounds produced by the air passing through it are strengthened by its resonance. The larger the nasal cavity the more powerful the resonance, and consequently the re-enforcement experienced by the tone. Sounds uttered with the nasal resonance, particularly the nasal vowels, are fuller and more ample than the same sounds when strengthened by the resonance of the cavity of the mouth, and it is for this reason that third-rate tragic actors like to give a nasal resonance to all the vowels in the pathetic speeches of their heroic parts. The resonance of the nasal cavity plays a part also in the formation of non-nasal articulate sounds; then, however, appearing only as a re-enforcement of the resonance of the cavity of the mouth. The directly excited nasal resonance sometimes plays an immediate part in the formation of all articulate sounds, producing the nasal "twang." But the general conception of this mode of speaking is by no means scientifically correct, every species of pronunciation in which the nasal element asserts itself with undue prominence being called "talking through the nose." It may, however, arise from two unlike causes: firstly, from a stoppage of the nasal cavity; or, secondly, from incomplete closure of the posterior entrance to this cavity. If the nasal cavity is obstructed, as when a child's nose is pinched and he is told to say "pudding," an accumulation of air forms in the back of the mouth, being unable to escape through the nose, and in the end is obliged to find exit through the mouth. The resonance is also altered, and the nasal sounds are, therefore, formed imperfectly and falsely. The same disturbance is produced by the partial obstruction of the nasal cavity which is experienced from the swollen condition of the mucous membrane, and from its increased secretion, during a "cold in the head."
A nasal twang from improper escape of air through the nasal cav-