Japanese, Korean and Vietnamese belong to three unrelated families. Their grammars have little in common. Yet they share thousands of words, because all three spent centuries borrowing from Chinese — and those borrowings followed regular sound patterns that are still visible.
The same word, three ways
| Meaning | Chinese | Japanese | Korean | Vietnamese |
|---|---|---|---|---|
| country | 國 guó | koku / kuni | guk 국 | quốc |
| university | 大學 | daigaku | daehak 대학 | đại học |
| library | 圖書館 | toshokan | doseogwan 도서관 | thư viện |
| telephone | 電話 | denwa | jeonhwa 전화 | điện thoại |
| student | 學生 | gakusei | haksaeng 학생 | học sinh |
| safety | 安全 | anzen | anjeon 안전 | an toàn |
The correspondences are systematic. Once you notice that Japanese gaku, Korean hak and Vietnamese học all render 學, you can predict a good deal — gakusei, haksaeng, học sinh for student follow automatically.
The borrowings came from different periods of Chinese. Japanese has several layers — go-on, kan-on and tō-on readings from successive waves of contact — which is why one character can have multiple Sino-Japanese readings. Vietnamese borrowed heavily from Middle Chinese and preserves distinctions Mandarin has since lost.
Some useful correspondences
| Sino-Japanese | Sino-Korean | Sino-Vietnamese | Example |
|---|---|---|---|
| -aku, -oku | -ak, -ok | -ac, -oc | gaku / hak / học |
| -atsu, -etsu | -al, -eol | -at, -iet | hatsu / bal / phát |
| -in, -an | -in, -an | -ân, -an | jin / in / nhân |
| -ou | -o, -yo | -ương, -ong | dou / do / đường |
Japanese lost the final consonants that Korean and Vietnamese kept, converting them into extra syllables — which is why Sino-Japanese words tend to be longer than their counterparts.
Native and Sino layers coexist
All three languages keep a native word alongside the borrowed one, usually with the native word being more everyday and the Sino word more formal — exactly the relationship English has between Germanic and Latinate vocabulary.
| Language | Native | Sino | Meaning |
|---|---|---|---|
| Japanese | yama | san | mountain |
| Japanese | mizu | sui | water |
| Korean | mul 물 | su 수 | water |
| Korean | hana 하나 | il 일 | one |
| Vietnamese | nước | thủy | water |
| Vietnamese | núi | sơn | mountain |
Korean's two number systems are the clearest case: native numbers for counting objects and ages, Sino numbers for dates, money and phone numbers. Both must be learned, and which one to use is determined by context.
Modern coinages travelled back
The flow was not one-way. In the nineteenth century Japan coined a large number of compounds to translate Western concepts — society, economy, science, freedom, philosophy — by combining Chinese characters. Those coinages were then adopted into Chinese, Korean and Vietnamese.
| Concept | Japanese coinage | Now also in |
|---|---|---|
| society | 社会 shakai | Chinese, Korean, Vietnamese |
| economy | 経済 keizai | Chinese, Korean, Vietnamese |
| philosophy | 哲学 tetsugaku | Chinese, Korean, Vietnamese |
How to use this
If you are learning a second East Asian language, keep a note of the Sino layer explicitly. When you meet a formal or academic word, ask whether you already know its counterpart in the language you studied first — you often will.
The caution is that meanings drift. Japanese 手紙 tegami means letter; the same characters in Chinese mean toilet paper. Treat the correspondence as a strong hint to be confirmed, not as a guarantee — which is exactly how the root-based approach works in Arabic and in Greek and Latin roots too.
Dictionaries for all three
NDT Studio publishes free offline dictionaries for Japanese, Korean and Vietnamese — including Vietnamese pair dictionaries. No connection needed.
Open the dictionary appFrequently asked questions
Are Japanese, Korean and Vietnamese related to Chinese?
No. All three borrowed heavily from Chinese over many centuries, but none descends from it. Japanese and Korean are not demonstrably related to Chinese at all, and Vietnamese is Austroasiatic, related to Khmer. The shared vocabulary is contact, not ancestry.
How much of these languages is Chinese-derived?
Estimates commonly run around 60 percent of the Japanese lexicon, a similar or higher figure for Korean, and a substantial share of Vietnamese, concentrated in formal, academic and technical registers. Everyday basic vocabulary is mostly native in all three.
Does learning one help with the others?
For vocabulary, considerably. The sound correspondences are regular enough that a Sino-Japanese word often predicts its Sino-Korean and Sino-Vietnamese counterparts. Grammar does not transfer at all — the three languages are structurally very different.