DYNAMICAL STUDY OP THE VOWEL SOUNDS 



103 



drawing conclusions from such diagrams as these, we must take care, 

 of course, to use only the broadest features revealed by the series.^ 



It is evident that for the sounds on the left leg of the usual triangle 

 (Fig. 3) (with the exception of short u), the inner orifice (that between 

 the back of the tongue and the soft palate) is much constricted, and we 



00 (fool) 



(team) 



Fig. 3 — Conventional vowel triangle 



have here a loosely-coupled system to deal with. Also, due to the 

 rearward position of most of the tongue structure, the mouth cavity 

 appears larger than the pharynx. Here we must realize the horizontal 

 width of these cavities, as well as their vertical extent. For the sounds 

 on the right of the triangle, the tongue goes forward in such a way that 

 the front cavity becomes the smaller of the two, and the connecting 

 (inner) orifice becomes larger; the system then becomes closely coupled. 

 For some of the sounds it is not a difficult matter to get fair values 

 for the conductivity of the mouth opening; this is approximately a 

 circle, or an ellipse of moderate eccentricity in these cases. (The con- 



^ I understand that Prof. G. Oscar Russell, Director of the Phonetics Laboratory, 

 Ohio State University, has made a remarkable series of clear X-ray photographs of 

 tongue and mouth positions, for the various vowel sounds, some of which he has 

 kindly shown me. He has worked out a special technique for making these pictures, 

 and is now engaged in a thorough study of them, which will ultimately be published 

 in monograph form. Unfortunately it is not possible to reproduce the pictures here; 

 but it may be stated that the series follows (but in a more systematic way) the general 

 course exhibited by the Rippmann diagrams shown in Fig. 2 of the present paper. 

 The comparison between the results sketched in the present paper for the mouth 

 cavities and results later to be published by Professor Russell should make a most 

 interesting study. 



