The Nature of Speech and Its Interpretation

V ARIOUS phases of this subject h a v e received serious s t u d y by phoneticians, otologists, a n d physicists. On account of its universal In spite of the large a m o u n t of t i m e devoted to the subAt the present time the physical properties which interest, it has received a t t e n t i o n from m e n in m a n y branches of science. ject, the progress in u n d e r s t a n d i n g its f u n d a m e n t a l aspects has been rather slow. differentiate the various f u n d a m e n t a l speech sounds are understood in only a very f r a g m e n t a r y w a y . Some very interesting a n d painsA l t h o u g h several t a k i n g w o r k has been done on the physical analysis of vowel sounds, b u t the results to d a t e are far from conclusive. theories h a v e been advanced to explain the w a y in w h i c h t h e ear interprets sound waves, they are still in the controversial stage. T h e material which is presented here is the result of an investigation which has been carried on in the Research Laboratories of the American Telephone and Telegraph Company and Western Electric C o m p a n y d u r i n g the past few years. To m a k e a q u a n t i t a t i v e s t u d y of speech a n d hearing it is necessary to o b t a i n the speech sounds at v a r y i n g degrees of loudness a n d w i t h definitely k n o w n a m o u n t s of distortion. T h e m a i n reason w h y so few real results have been o b t a i n e d in the investigation of speech sounds is d u e to the fact t h a t it is extremely difficult to change the v o l u m e a n d distortion of these sounds by acoustic means.