This study investigates Sino-Japanese and Sino-Vietnamese cognates listed in the Old JLPT Vocabulary List and examines their relevance for Japanese language education. Focusing on kanji-only vocabulary, it extracts and classifies one- and two-character items and analyses correspondences in written form, core meaning, and grammatical function. Using dictionarybased comparison supplemented by checks from highly proficient native Vietnamese speakers, the study identifies many same-form cognates, particularly in academic, administrative, scientific, and abstract domains. It also shows that about 18.8% of same-form two-character items exhibit part-of-speech mismatches, such as noun–adjective and noun–verbal noun correspondences, which may lead to negative transfer. Overall, the findings indicate both the pedagogical value of same-form cognates and the need for instructional approaches that account for grammatical differences.

The study investigates the phenomenon of corresponding Chinese characters in relation to Sino-Vietnamese elements (SVEs). Generally, each SVE corresponds to one Chinese character. However, the SVE system also contains cases in which multiple SVEs share similar or corresponding Chinese characters. Among 3,010 commonly used SVEs, 201 elements were identified as having similar corresponding Chinese characters, accounting for 6.6% of the data surveyed. The phenomenon of corresponding Chinese character similarity in SVEs is formed based on the relationship between SVEs and their corresponding Chinese characters in terms of pronunciation and meaning. This phenomenon is categorized into two groups: the first group is formed based on the adaptation of Chinese characters with multiple pronunciations; the second group is formed based on the adaptation of Chinese characters with multiple meanings. The number of SVEs in group 1 includes 129 elements、 accounting for 64%, while group 2 includes 72 elements, accounting for 36%. This reflects that the formation of SVEs tends to favor phonetic compatibility over semantic compatibility with the original Chinese characters. This phenomenon differs from the phenomenon of phonetic variation in SVEs. Though both phenomena share similarities in terms of their correlation with Chinese script and linguistic complexity, they differ in meaning and substitutability. In terms of origin, phonetic variation arises from factors such as name taboo、 phonetic distortion, and linguistic habit. In contrast, the phenomenon of corresponding Chinese character similarity in SVEs reflects the Vietnamese language’s ability to adapt Chinese script both selectively and creatively in terms of meaning. This phenomenon also demonstrates the capacity of Vietnamese to both preserve similarity and creatively modify pronunciation when assimilating Chinese script. The methods of expanding pronunciations in SVEs (five methods) reflect the diversity and also the lack of standardization in the process of forming this system of increased pronunciations. The phenomenon of corresponding Chinese character similarity in SVEs also reflects the capacity for development and the influence of Chinese characters in terms of meaning and pronunciation within a distinct linguistic environment like Vietnamese.

The circulation of modern Chinese-character neologisms in East Asia has attracted considerable scholarly attention, yet research on the Vietnamese context remains insufficient. This article reviews existing academic work on the topic and examines both the sources of Sino-Vietnamese neologisms and the routes through which they were transmitted. Primary source materials include Sino-Nôm “new books,” textbooks, dictionaries, newspapers, writings by Vietnamese students returning from Japan, and texts authored by communist revolutionaries. There are two main transmission routes for these neologisms into Vietnam: one from China, primarily through publications from Shanghai and revolutionary circles in Guangzhou; the other from Japan, via Vietnamese students involved in the Đông Du (Go East) movement. The study argues that Vietnam’s reception of these Chinese-character neologisms reflects its efforts toward linguistic modernization and highlights the complex network of cultural interactions within East Asia.

The system of Sino-Vietnamese elements and Chinese characters have a relationship which has developed over the two thousand years since the beginning of the Christian era. This relationship can be divided into three phases based on the status and influencing level of Chinese characters in Vietnam including: from the prehistory to the tenth century, from the eleventh century to the beginning of the twentieth century, and from the early twentieth century to the present. In the first phase, the Sino-Vietnamese element system was formed. In the second phase, it was developed together with Chinese characters in Vietnam. In the third phase, it has been developed together with Vietnamese script, moving away from Chinese characters. This paper surveys this relationship based on 500 Sino-Vietnamese elements currently existing in Vietnamese. In this relationship, the Sino-Vietnamese elements borrow the meaning of the Chinese characters including the wholly borrowing ones (accounting for 3%）and the partially borrowing ones (accounting for 97%). The Sino-Vietnamese elements borrowing the original meaning of Chinese characters account for 57% while those do not account for 43%. The independently used Sino-Vietnamese elements account for 18%, and the non-independently used account for 82%. Some elements which create new meanings account for 8% whereas those which do not account for 92%. With such borrowing and creating characteristics, the system of Sino-Vietnamese elements has evolved and developed in terms of meaning. The ability to create words of the Sino-Vietnamese element system is created by turning morphemes into one-syllable words, combining morphemes, and repeating morpheme. The repeating method has little effect on the foreign elements. The method of turning morphemes into one-syllable words forms a number of word classes, accounting for 18%. The combining method is formed when combining Sino-Vietnamese elements together or combining Sino-Vietnamese elements and non-Sino-Vietnamese elements. This method forms precedent or unprecedented words in Chinese. The characteristics of creating the meaning and the ability to form words of the Sino-Vietnamese element system have proved the vitality, adaptability, and strong development of the Sino-Vietnamese element system as a word forming element system in Vietnamese. In the context of written language development in Vietnam today, the previous parallel relationship between the system of Sino-Vietnamese elements and Chinese characters has been severely damaged. Most Vietnamese users no longer have a clear understanding of the relationship and cannot trace the origin of Sino-Vietnamese elements. Therefore, reconstructing the relationship, studying its value, and creating search tools have become critical. This contributes to helping Vietnamese users understand more deeply and use more accurately the Sino-Vietnamese element system in Vietnamese.

Sino-Vietnamese pronunciations are the way Vietnamese people read Chinese characters. Going through the process of formation and development, they have become an important part of the Vietnamese language. In the field of literature, Sino-Vietnamese sounds are closely related to Tang poetry in China and Tang poetry in Vietnam. Tang poetry is a Chinese literary achievement consisting of systems of authors and works with strong influences on Sinosphere countries in medieval time such as Vietnam, Japan, and Korea. In Vietnam, Tang poems are read by Sino-Vietnamese pronunciations, which ensure tonal harmony. Scholars in China, Vietnam, and other countries have studied Tang poetry in terms of phases, authors, styles, and ideologies. However, there has been no attempt to investigate the characteristics and functions of Sino-Vietnamese pronunciations in Tang poetry. In this paper, we study the characteristics and functions of Sino-Vietnamese pronunciations in Tang poetry in China and Vietnam based on the comparison of similarities and differences of reading Tang poems by Sino-Vietnamese pronunciations and by contemporary Chinese by means of surveying 133 poems in Three hundred Tang poems. Comparative data on the ability to keep Tang poetry’s same tone rules and Tang poetry’s rules of Sino-Vietnamese pronunciations and contemporary Chinese show that both types of reading can either remain or break the rules of this poetry type, but their proportions are different. 54% of poems by Sino-Vietnamese pronunciations keep Tang poetry’s same tone rules and Tang poetry’s rules while the rate of poems by contemporary Chinese reading is 34%. The number of poems in which Sino-Vietnamese pronunciations can keep the rules while contemporary Chinese cannot is 28 (accounting for 21%). The number of poems in which contemporary Chinese can keep the rules while Sino-Vietnamese pronunciations cannot is 1 (accounting for 1%). The survey results show the remarkable advantages of Sino-Vietnamese pronunciations regarding the ability to keep Tang poetry’s same tone rules and Tang poetry’s rules compared to the contemporary language used by Chinese people. This is attributed to the fact that Sino-Vietnamese pronunciations are close to the sounds of Tang poetry and still preserve the tone patterns. With such a characteristic, in the process of cultural adaptation, Vietnamese people use Sino-Vietnamese pronunciations to compose, translate, as well as appreciate and study Tang poems. There were thousands of authors, and there were poetry collections of thousands of Tang poems written in Sino-Chinese in medieval time. The similarities and differences between Sino-Vietnamese pronunciations and contemporary Chinese in Tang poems prove cultural adaptation among nations, contributing to preserving the diverse beauty of valuable literary works of humankind.