Coined by Mongolian politician, revolutionary and linguist Khaisan in 1917 in 《蒙漢合璧五方元音》 ("Mongolian-Han Bilingual Original Sounds of the Five Regions"), an edition of the Mandarin rime dictionary《五方元音》 ("Original Sounds of the Five Regions") which included Mongolian transliterations of Mandarin readings.[1]
^ Wu, Jiaye (2022) “Teaching Mandarin Pronunciation to Mongolian Learners in Early Republican Period China: The Case of the Mongolian Han Original Sounds of the Five Regions”, in Nicola McLelland and Hui Zhao, editors, Language Standardization and Language Variation in Multilingual Contexts, →ISBN