ARTICULATION TESTING METHODS 



815 



articulation by means of the above curve. The value so obtained is 

 taken as the average syllable articulation for the test. 



The articulations for the various sounds are recorded on the Articu- 

 lation Test Analysis Record of Table IV. In making the analysis 

 the total errors for each caller are counted. The occurrences per 

 caller are the products of the number of times the sounds are spoken 

 by the caller, and the number of observers. One analysis sheet 

 contains the results for a complete test. 



20 



40 60 



ARTICULATION 



Fig. 1 — Averaging factor curve 



In dealing with the syllable articulation the unit is 66 called syllables, 

 or the result of one caller and one observer. Hence a number of 

 syllable values are obtained for one test which are averaged by 

 means of the averaging factor curve. When we deal with the articu- 

 lation of the individual speech sounds, it is advisable to use a larger 

 unit since each sound occurs only six times in a 66 syllable unit. 

 In Table IV the errors are shown for each caller as a unit, and since 

 there were 7 observers per caller, each sound occurs 42 times. This 

 is a unit of sufficient size to qualitatively compare various voices. 

 However, in drawing conclusions as regards the effects of the circuit 

 upon the transmission of the various sounds, it is best to use eight 

 callers as a unit, so that each sound, depending upon the number of 

 observers, occurs of an order of 200 to 300 times. In this case the 

 articulation of an individual sound has a precision that is comparable 



