the teeth-ridge when the tongue is in the position of rest is called the blade. The extremity of. the tongue is called the tip, and is included in the blade. The definitions of “back” and “front” are particularly important.
34. The vocal chords are situated in the larynx; they resemble two lips (see fig. 4). They run in a horizontal direction from back to front. The space between them is called the glottis. The chords may be kept apart or they may be brought together so as to close the air passage. When they are brought close together and air is forced between them they vibrate, producing a musical sound. (see Chap. V).
CHAPTER IV
EXPERIMENTAL METHODS
*35. The analysis of sounds in general and the differences between English sounds and foreign sounds which resemble them, may, if desired, be investigated and demonstrated by means of specially designed apparatus. Such demonstrations belong to the branch of phonetic science known as “instrumental” or “experimental” phonetics.
*36. It is not suggested that experimental phonetics is a necessary study for all those who wish to pronounce a foreign language correctly, but demonstrations by means of special apparatus are often found helpful by students as fixing in the memory that which they have previously learned by the ordinary methods of practical phonetics. The parts of this book relating to experimental phonetics may be entirely omitted by those who have not time or opportunity to take up this branch of the subject. Paragraphs which may be so omitted are marked with an asterisk *.
*37. The apparatus used in elementary instrumental phonetics includes the artificial palate, the kymograph, the laryngoscope, the mouth measurer, the gramophone and other talking machines, and a number of less important instruments.
*38. The artificial palate being referred to constantly throughout this book, it is convenient to give here a description of it, and an explanation of the mode of using it. The kymograph and the experiments which may be done with it are dealt with in Chapter XXI. The other instruments are described under the experiments for which they are used (laryngoscope § 46, quadrant indicator § 85, mouth measurer § 84).
*39. The artificial palate is used for recording the points of contact of the tongue with the palate in pronouncing sounds. Suitable artificial palates may be made of metal, vulcanite, or prepared paper. The material must be very thin, it must fit the observer’s mouth
