Ths is a system of traditional Chinese characters, keeping the original form, transcribed into Yao language. Over time, they "changed" the pronunciation and kept the original meaning of the words. This pronunciation is completely different from the Yao language used in daily life. They also received some Nom Tay and Nom Viet words that the Yao language did not have. This font can only be used by people who can read and write. This writing system was used by previous Yao intellectuals in all Yao documents, from learning books to recording days, months, poems, literature... Most of the families have tall people. All of them still keep the old books left by their fathers. These books reflect all aspects of the material and spiritual life of the Yao people in the past.