PSYCHOLOGY 277 



into one another, and are therefore, especially as regards con- 

 sonants, very difficult to imitate. On this account Tiirkheim's 

 assertion that no animal is capable of more than four sounds 

 should be received with the greatest caution. But even if it 

 were so that the particular utterances of the separate species of 

 animals merely ring the changes on the four letters, yet animal 

 speech ought not to be described on that account as poor, for 

 the four letters may be compared to the primitive syllables 

 which often do not contain even four letters and yet have 

 formed the roots of the human language. 



The voice-organ of the Vertebrates capable of vocalisation 

 and of man is the larynx, with the cavity of the mouth as an 

 accessory pipe. The voice is mainly produced by expiration, 

 but in man and many animals it may be inspiratory as well. 

 In those cases where inspiratory sounds figure in a language, as 

 for instance among the South African negroes, these so-called 

 " suction-tones " correspond to the noises of many animals. 

 The vowel sounds produced in the larynx are, according to 

 Helmholtz, not simple tones either in man or animals, but 

 clangs, consisting of a fundamental tone and numerous accom- 

 panying overtones. The muffled vowels O and U are not so 

 rich in overtones as the vowels A (ah), E (eh), I (ee). Every 

 vowel sound is produced by a definite arrangement of the mouth, 

 while the nasal cavity is shut off by contraction of the arch of 

 the palate and raising of the soft palate. The diphthongs Ae, Ai, 

 Ei, Au, Eu, are, according to Briicke, formed by a transition 

 from the arrangement necessary for one vowel to the next, and 

 during this movement the voice is emitted. For consonants the 

 cavity of the mouth acts as a speaking-trumpet in which at 

 particular places rubbing sounds or closed sounds are made. 

 As regards the half- vowels (liquids) these are M, N, Ng, L, 

 and the trilled R. 1 



Having briefly dealt with the speech of animals from a 

 general and physiological point of view, I propose discussing at 

 greater length the speech of apes, a theme which is of general 

 interest to physiological psychology and of supreme importance 

 to anthropology. Brehm 2 in his illustrated Animal Life de- 

 scribes the speech of apes as being fairly rich in modes of 



1 Munk-Schultz, loc. cit., p. 415. 2 Brehm, loc. cit., i., p. g. 



