ARTICULATION TESTING METHODS 807 



of public speakers, actors, students of foreign languages or pupils in 

 deaf schools who are learning to speak. 



The rating of auditors by measuring the recognizability of speech 

 sounds which they hear has been used to some extent. For example, 

 such methods have been used to determine the ability of students to 

 interpret a spoken foreign language. Also, the deafness of a person 

 can be determined by such methods. In this case, however, the 

 specialists have usually tried to vary transmission systems between 

 the speaker and listener so as to compensate for the loss of hearing, 

 the amount of such compensation being determined by measuring 

 the recognizability of speech sounds. 



The best method of determining the recognizability of the speech 

 sounds naturally depends upon which of the things just enumerated 

 is to be rated. In principle, the method in each case consists in the 

 pronunciation of "selected speech sounds" by a speaker, the trans- 

 mission of these sounds to an observer's ears, and the recording by 

 the observer of the sounds which he recognizes. Such methods 

 applied to telephone systems have been frequently referred to as 

 articulation tests. The term "articulation" would be more logically 

 used if it were applied only to cases where the speaking abilities of 

 persons are being determined. However, it has been used so fre- 

 quently in connection with rating transmission systems that it seems 

 convenient to retain it. 



The "selected speech sounds" which are ordinarily used in articu- 

 lation tests are meaningless monosyllables. The percentage of the 

 total number of spoken syllables which are correctly observed is 

 called the syllable articulation. This percentage has frequently been 

 called simply "the articulation." 



A syllable is considered to be incorrectly observed, if one or more 

 of the fundamental speech sounds which it contains are mistaken. 

 It is frequently desirable to analyze these mistakes and determine 

 the articulation of the speech sounds. The percentage of the total 

 number of spoken sounds which are correctly observed is called the 

 sound articulation. When the attention is directed toward a specific 

 fundamental sound, such as "b" or "t" or "a," etc., then the term 

 "individual sound articulation" is used. For example, the individual 

 sound articulation for "b" is the percentage of the number of times 

 that "b" was called that it was observed correctly. Similarly, the 

 terms "consonant articulation" or "vowel articulation" refer to the 

 percentages of the total number of spoken consonant or vowel sounds 

 which are correctly observed. 



The articulation values as defined above are taken as the measures 



