June 7, 1917] 



NATURE 



28s 



ANALYSIS OF THE MECHANISM OF 

 SPEECH. 



THE imj>etus which recent events have given to 

 the study of spoken languages has brought 

 with it a renewed interest in the scientific analysis 

 of the mechanism of speech. He who wishes to 

 learn how to sp>eak a foreign language must 

 necessarily devote much of his time to the acquisi- 

 tion of the pronunciation, and he will most easily 

 learn to become proficient at this difficult art if 

 he can ascertain precisely what he has to do with 

 his speech-organs in order to speak correctly. The 

 need for accurate information about speech move- 

 ments has led to the development of that branch 



tube is fitted (A) a mouthpiece (into which the 

 observer speaks), or (B) a nasal olive (which fits 

 into one nostril), or (C) a "larynx capsule " 

 (which is pressed firmly against the outside of the 

 larynx). These appliances are shown in Fig. 2. 



The complete apparatus is shown in Fig. 3, 

 which is an illustration of a small portable kymo- 

 graph. The diagrams in this article were made 

 on the large kymograph in the laboratory of ex- 



FiG. I,— A Marey tambour. MM, the membrane ; S, the style. 



of science known as experimental phonetics — the 

 branch of science which has for its object the 

 accurate analysis of speech by mechanical means. 



Among the numerous instruments which have 

 been devised for speech analysis there is one of 

 particular importance, known as the phonetic 

 kymograph, and it is the object of this article to 

 give a brief description of the nature and use of 

 this apparatus. 



The phonetic kymograph is essentially an appli- 

 cation of the Marey tambour to linguistic pur- 

 poses. The principle of this tambour is well 

 known, and it is not necessary to describe it in 

 detail. It will be sufficient to recall that it is a 



Fig. 3. — A small portable kymograph. 



perimental phonetics at University College, Lon- 

 don ; the cylinder of this machine has a circum- 

 ference of one metre and a maximum surface 

 speed of 70 cm. per second. 



The most useful single tracings that can be 

 made on the phonetic kymograph are those which 

 result from speaking into the mouthpiece. More 

 detailed information may, however, often be ob- 

 tained by taking nose and mouth tracings, or 

 mouth and larynx tracings simultaneously, or by 

 taking tracings of all three kinds at the same time. 



Fig. 2.— a, mouthpiece ; B, nasal olive ; C, larynx capsule. 



mechanism by which vibrating air is communicated 

 to an elastic membrane, and the vibrations of 

 this membrane are in turn communicated to a 

 very light needle or style (Fig. i). The vibra- 

 tions of the style are generally recorded on a 

 revolving drum covered with smoked paper or 

 some similar contrivance. Tambours may be of 

 various sizes and materials. A very useful type 

 is one in which the membrane is made of perished 

 rubber, and measures 3 cm. in diameter. 



Air vibrations set up by speech may be commu- 

 nicated to the tambour in three principal ways : 

 (i) from the mouth, (2) from the nose, (3) from 

 the outside of the larynx. A rubber tube is 

 attached to the tambour, and at the end of this 

 NO. 2484, VOL. 99] 



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Fig. 4. — Mouth-tracing oi potato. , 



The accompanying illustrations show the nature 

 of kymographic tracings and the deductions which 

 can be made from them. Fig. 4 shows a mouth- 

 tracing of the English word potato.^ The hori- 

 zontal parts of the line show the places where no 

 air issues from the mouth, i.e. the "stops " of the 

 consonants p, t, and t. The three steep rises in 

 the line mark the plosions of these consonants. 

 The small waves are caused by the air set in 

 vibration by the vocal chords when "voice" is 

 produced ; in this diagram they represent the 

 vowels. The regular wavy line figuring in this 

 and other illustrations is a time-measurer showing 

 hundredths of a second. 



Various features of pronunciation may be 



1 The lettering appearing in this and other diagrams is a phonetic tran- 

 scription of the pronunciation (International Phonetic system). 



