Vietnam is a multi-ethnic country with many cultures, languages, and forms of texts that coexist independently and interactively. Among the Vietnamese ethnic minorities is the Tay, the most primarily populated one. Before the use of the Latinized script, the Tay people used to use Nom which is made up of the graphic, phonetic and semantic elements of Han characters. Currently, the cultural source of the Tay is one of the most precious cultural heritages of Vietnam. If we want to decode, research, explore and promote the values of this heritage, it is impossible not to have a good set of reference books, which are Nom-Tay (word-based and character-based) dictionaries. It is undeniable that the compilation of Tay-language dictionaries and texts has attracted interest, and been in implementation for about half a century, thanks especially to the government, research institutions, and generations of Vietnamese scholars. However, the achievements have not met the needs and utilization potential of the explored materials. With the extremely abundant resources of ancient Nom-Tay texts, with the proper attention and investment of the state and investment funds, and with researchers’ enthusiasm, the compilation of the Nom-Tay (word-based and character-based) dictionaries will, to be sure, attain remarkable achievements.

The development of Nom characters is promoted on the basis of and in attachment with Chinese characters, and in this regard the Phonetic Annotation of the Thousand Character Classic 《千字文解音》 compiled in the late Nguyen Dynasty in Vietnam was a very practical textbook for learning Chinese characters and Nom characters. Based on categorizing Nom characters, the paper intends to clarify several notions on Nom characters of the Phonetic Annotation of the Thousand Character Classic. In the beginning, Nom characters can be divided into two major types: the directly borrowed Chinese characters and the independently invented ones. The former includes borrowing sounds, meanings, and both. The latter, according to the components of Chinese character formations, can be divided into the pictophonetic of Chinese characters and that of Nom characters. In the last part of the article, we summarize the relationship between Chinese characters and Nom characters. It is necessary not merely to consider the relationship but to understand the comparisons between them. With the aid of studying Nom characters, we can find that irrespective of whether they are directly-borrowed from Chinese or independently invented, the sound of Chinese characters is the most important feature for them. But we cannot ignore the ideographic parts of Nom characters because they, on the one hand, make up the phonetic deficiency of Chinese characters while promoting the development of Nom characters on the other. In our modern society, Chinese characters and Nom characters came to drift apart, and the latter especially was withdrawn from the historical stage, but the traditional culture of Vietnam is still recorded in literature both in Chinese characters and Nom characters. Moreover, the Nom character is one of the most important representatives of Vietnam’s traditional culture. For this reason solely, this research shall be a great help to further understanding of significant cross-cultural aspects between China and Vietnam, and more specifically of histories related to the spreading, application, and development of Chinese characters in Vietnam.