Why Chinese, Japanese, Korean and Vietnamese share so many words
About half of Japanese and Korean vocabulary and most of Vietnamese came from Chinese. Here is how it happened, and why it makes learning all four at once easier than it sounds.
Say “university” in Mandarin and you get dàxué. In Japanese it is daigaku, in Korean daehak, and in Vietnamese đại học. These are not four languages that happen to sound alike: they belong to unrelated families. They share the word because all four borrowed it from the same place, written with the same two characters, 大學.
| Hanzi | 中 | 日 | 한 | Việt |
|---|---|---|---|---|
| 大學university | dàxué | daigaku | 대학daehak | đại học |
| 經濟economy | jīngjì | keizai | 경제gyeongje | kinh tế |
| 注意attention | zhùyì | chūi | 주의juui | chú ý |
| 電話telephone | diànhuà | denwa | 전화jeonhwa | điện thoại |
| 革命revolution | gémìng | kakumei | 혁명hyeongmyeong | cách mạng |
A shared classical language
For well over a thousand years, Literary Chinese was to East Asia what Latin was to Europe: the language of government, scholarship and religion. Under the Tang dynasty (618–907) Chinese writing, learning and culture spread wholesale to Korea, Japan and Vietnam. Scholars there read the classics aloud in their own approximation of the Chinese of the time, and the words they read entered their everyday speech.
Each country took them in its own way. Northern Vietnam was ruled from China from 111 BC to AD 938, and its Chinese layer took shape in the Tang. In Korea the flow became overwhelming once civil service examinations in Chinese began in 958. Japan received several waves: readings that came with Buddhism by way of Korea in the 6th century, Tang-era readings brought home by students of China, and later ones brought by Zen monks.
In 1953 the linguist Samuel Martin named these borrowed layers “Sino-Xenic”, from Greek xénos, “foreign”: Chinese as pronounced abroad. They are the root of our name, Sinoxenica.
How much is borrowed?
A great deal. A 2025 review of the counts by the linguist Hitomi Kinoshita, in the research papers of Japan’s National Institute for Japanese Language and Linguistics, puts Chinese-origin words at about 43–54% of the vocabulary of Japanese and 47–56% of Korean, depending on the kind of text, and around 70% for Vietnamese. They are concentrated in exactly the words a learner needs past the beginner stage: politics, science, business, the news.
The sounds changed, regularly
The words drifted apart in sound as each language changed, but they drifted in regular ways. Medieval Chinese words could end in -p, -t or -k. Vietnamese kept those endings; Korean kept -p and -k and turned -t into -l; Japanese, which allows almost no final consonants, added a vowel; Mandarin dropped them altogether. Once you know a few of these correspondences, a word in one language often lets you guess its reading in the others.
| Hanzi | 中 | 日 | 한 | Việt |
|---|---|---|---|---|
| 國country | guó | koku | 국guk | quốc |
| 學study | xué | gaku | 학hak | học |
| 日sun, day | rì | nichi | 일il | nhật |
Words that travelled back
The borrowing did not only run outward from China. In the late 19th century Meiji Japan coined hundreds of new words from Chinese characters for Western ideas, such as 哲學 “philosophy”, 社會 “society” and 電話 “telephone”, and gave old ones new meanings: the classical 革命 became “revolution”. Many of them were then borrowed into Chinese, Korean and Vietnamese, which is why the vocabulary of modern life is shared as well as the classical one.
Where they part ways
Shared characters are a strong hint, not a guarantee. 新聞 means “news” in Chinese but “newspaper” in Japanese and Korean. Chinese, Japanese and Korean call a library 圖書館, while Vietnamese says thư viện, 書院. And each language keeps a large native vocabulary of its own for the most everyday things.
This shared layer is what Sinoxenica is built on: learn a character and its family of words once, and recognize them in four languages.