Taboo character is typical phenomenon of Chinese characters system, it is considered as the effective key in decrypting the date of Han-Nom texts inscirption texts. Such key is maintained clearly on the ancient books add steles of Vietnam, specially Taboo characters system in the insription texts of Tran Dynasty (1225-1400). Based on research results, we have found a new form of Taboo character previously published in studies in Vietnam Taboo characters. Such new characters forms have helped us easily discover in cription texts at the date of Tran dynasty in Ninh Binh. This is the useful and reliable source for researching of Vietnam Taboo characters in particular and ancient books of Vietnam in general.

Basing on analyzing the linguistic material in Quốc âm thi tập (􀊆􂙌􆜴􅦪 􆘇􀊇) written by Nguyễn Trãi 􆕯􂸍 (1380-1442), this article conducts a research on Chinese-borrowed words in ancient Vietnamese, and develops several concepts to classify Chinese-borrowed words. Due to the author’s viewpoint, ‘Vietnamese Chinese-loaned word’ refers to all Vietnamese words borrowed from Chinese language and Chinese scripts that were used in the 15th century Vietnamese language. This article then argues, the influence of Chinese scripts and language on the 15th century Vietnamese is so strong that it could help to contribute 63.37% rate of the Vietnamese vocabulary.