This study examines the pronunciation of announcers, who are articulatory experts, with the aim of pragmatically resolving the argument over the Korean monophthongal system, which has variously been proposed to consist of seven to ten vowels. If monophthongs are not observed to occur in the standard pronunciation of announcers, then what has traditionally been viewed as ‘standard pronunciation’ is nothing but a pronunciation system of the past that has disappeared. As for the pattern of articulation of /ㅚ/, /ㅟ/, it was found that no announcers articulated both of these vowels as monophthongs. Though there were two announcers who articulated /ㅚ/ as a monophthong, and two other announcers who articulated /ㅟ/ as a monophthong, there were not any announcers who articulated both vowels as monophthongs. These results reflect the difficulty of maintaining the argument for the monophthongal status of these vowels any longer. As for /ㅔ/, /ㅐ/, a process of confluence was conspicuously observed in the speech of announcers as indicated in previous studies. The difference appeared clearly only for announcers in their 50s or older who pronounced the vowels after concentrating on monophthongs in isolation. It was difficult to observe the difference clearly when announcers in their 50s spoke full words, or when announcers in their 40s or younger spoke. As for /ㅗ/, /ㅜ/, a phonetic characteristic was discovered that the tendency contrasted by the height of the tongue changed into a contrast in the backness of the tongue. Compared to the loss of auditory perceptive discrimination of /ㅔ/, /ㅐ/ due to their confluence, there was a shift in the position of articulation for /ㅗ/, /ㅜ/, but in that it maintains auditory perceptive discrimination, it can be predicted that the discriminative characteristics of /ㅗ/, /ㅜ/ may change the backness of the tongue in a phonetic manner. (KAIST and Konkuk University)