These forms of defective speech are manifested by the inability to express words in the normal, natural manner—freely and fluently. In other words, there is a marked departure from the normal in the methods used by the stammerer in the production of speech. It is necessary, therefore, before taking up the discussion of the causes of stuttering and stammering, to determine the method by which voice is produced in the normal individual, so that we can compare this normal production of speech with the faulty method adopted by the stutterer or stammerer and learn where the fault is and what is the cause of it.

Let us now proceed to do this: In other words, let us ask the question: "How is speech produced in the normal person not afflicted with defective utterance?"

Voice is produced by the vocal organs much in the same manner as sounds are produced on a saxophone or clarinet, by forcing a current of air through an aperture over which is a reed which vibrates with the sounds. The low tones produced by the saxophone or clarinet result from the enlargement of the aperture, while the higher tones are produced by contracting the opening. Variations of pitch in the human voice are also effected by elongation and contraction of the vocal cords with comparative slackness or tension, as in the violin.

It would be of no value, and, in fact, would only serve to confuse the layman, to know the duties or functions of the various organs or parts entering into the production of speech. Suffice it to say that in the "manufacture" of words, there are concerned the glottis, the larynx, thorax, diaphragm, lungs, soft palate, tongue, teeth and lips. In the production of the sounds and the combination of sounds that we call words, each of these organs of speech has its own particular duty to perform and the failure of any one of these organs properly to perform that duty may result in defective utterance of some form.

BRAIN CONTROL: It must be borne in mind that for any one or all of the organs of speech to become operative or to manifest any action, they must be innervated or activated by impulses originating in the brain.

For instance, if it is necessary that the glottis be contracted to a point which we will call "half-open" for the production of a certain sound, the brain must first send a message to that organ before the necessary movement can take place. In saying the word "you," for instance, it would be necessary for the tongue to press tip against the base of the lower row of front teeth. But before the tongue can assume that position, it is necessary that the brain send to the tongue a message directing what is to be done.

When the number of different organs involved in the production of the simplest word of one syllable is considered (such as the word "you" just mentioned), and when it is further considered that separate brain messages must be sent to each of the organs, muscles or parts concerned in the production of that word, then it will be understood that the process of speaking is a most complicated one, involving not only numerous physical organs but also intricate mental processes.

When all of the organs concerned in the production of speech are working properly and when the brain sends prompt and correct brain impulses to them, the result is perfect speech, the free, fluent and easy conversation of the good talker. But when any or all of these organs fail to function properly, due to inco-ordination, the result is discord—and defective utterance.

CAUSE OF DEFECTIVE UTTERANCE: Now, let us consider the cause of defective utterance. What is it that causes the organ, muscle or parts to fail properly to function? The first and most obvious conclusion would be that there was some inherent defect in the organ, muscle or part which failed to function. But experience has proved that this is usually not the case. An examination of two thousand cases of defective utterance, including many others besides stuttering and stammering, revealed three-tenths of one per cent. with an organic defect—that is, a defect in the organs themselves. In other words, only three persons out of every thousand afflicted with defective utterance were found to have any physical shortcoming that was responsible for the affliction.

Take any of these two thousand cases—say those that stammered, for instance. What was the cause of their difficulty, if it did not lie in the organs used in the production of speech? This is the question that long puzzled investigators in the field of speech defects. Like Darwin, they said: "It must be this, for if it is not this, then what is it?" If stuttering and stammering are not caused by actual physical defects in the organs themselves, what then can be the cause?