CHAPTER LXVIII 



Speech 



O. L. ZANGWILL 



The Psychological Laboratory, University of Cambridge, Cambridge, England 



CHAPTER CONTENTS 



Speech Perception 



Effects of Stimulus Distortion 



Masking of Speech 



Binaural Speech Perception 



Aural 'Monitoring' of Speech 

 Speech Production 



Respiratory Movements in Relation to Speech 



The Vocal Cords 



Neurophysiology of Phonation 



Oral Movements in Speech 



Esophageal Speech 

 Neurology of Speech 



Bulbar Syndromes 



Midbrain and Cerebellar Syndromes 



Apraxic Dysarthria 



Aphasia 



Phonetic Disintegration in Aphasia 



Auditory Defects in Aphasia 



Aphasia and Cerebral Localization 



Induced Vocalization and Speech Arrest 



Cerebral Dominance 



Stuttering and Kindred Speech Defects 



Development of Speech 



although the orioins of speech remain obscure, its 

 evolution from some primitive form of animal com- 

 munication is nowadays taken as established. In 

 particular, the discovery by von Fritsch (136) of an 

 elaborate system of gestural communication in the 

 social insects has finally disposed of the view thai 

 propositional language is an exclusively human 

 attribute. In the bee at least, communication as 

 concise and explicit as a system of naval signals 

 dominates social organization (102, 127, 136). Recent 

 cthological work further suggests that mechanisms 

 of communication play a far more important role 

 in vertebrate behavior than had previously been 

 supposed (49, 127, 129, 130). Although some authors, 



such as Revesz (104), deny the relevance of 'animal 

 languages' to the understanding of human speech, 

 communication is nowadays accepted as a biological 

 fact of the first importance. 



The mode of evolution of human spcecli remains 

 wholly conjectural. The limitation of speech in the 

 anthropomorphous apes is usually thought to be due 

 to lack d1 appropriate specialization within the 

 central nervous system. On the oilier hand, studies 

 11I phonation in the chimpanzee have suggested that 

 absence <>l speech is more closely dependent on 

 morphological peculiarities of the larynx itself (66). 

 One recent author, however, has argued that trans- 

 loi in.ition of the larynx and the organs of the vocal 

 cavit) subserving articulation occurred before the 

 evolution of the hominids (68). This whole matter is 

 deser\ ing of further study. 



In the study of human speech, contemporary lines 

 of inquiry are so diverse as to defeat adequate sum- 

 mary. Apart from developments in formal linguistics 

 ill 87), psychophysical studies of speech processes 

 have multiplied rapidly in recent years and now 

 dominate an important area of experimental psy- 

 chology (80, 84-86, 92). The genetic study of language 

 has also shown progress, particularly under the 

 stimulus of Piaget (82, 98). In neurology, aph.isi.i 

 and kindred disorders of speech continue to claim 

 attention and their study has given rise to some fresh 

 concepts of cerebral function (2, 27, 28, 43, 63). On 

 the other hand, neurophysiologies! studies bearing 

 on speech have been distinctly sparse; there is no 

 general review of the subject in English more recent 

 than that of Kerridge (67) in 1938. This is no doubt 

 due in part to limitations of technique and in part to 

 the prevalent concern of investigators with the wider 

 problems of language and communication, more 

 especially in their technological aspects (37, 86, 1 1 7). 

 Although work stimulated by, or related to, com- 



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