'Phags-pa script
The book is written in Chinese using a mixture of Chinese characters and 'Phags-pa transcription, with section titles and rime class headings given in both scripts. Only the two prefaces and the appended list of taboo characters are written entirely in Chinese characters. The title of the book in 'Phags-pa script ( "mong xol tshi ʼwin") is anomalous in that it does not exactly transcribe the corresponding Chinese characters ("Měnggǔ Zìyùn" 蒙古字韻) as "mong xol" is not a transcription of the Chinese characters 蒙古 (měnggǔ, meaning 'Mongol'), but is a direct phonetic representation of the Mongolian word "mongɣol" 'Mongol'.