|Vietnamese alphabet||từ Hán-Việt|
Sino-Vietnamese are the elements in the Vietnamese language derived from Chinese. They account for between 30% and 60% of the Vietnamese vocabulary, not including calques from China. This vocabulary was originally written with Chinese characters that were used in the Vietnamese writing system, but like all written Vietnamese, is now written with Vietnamese alphabet, the Latin-based Vietnamese alphabet that was adopted in the early 20th century for writing the Vietnamese language.
The term Sino-Vietnamese was used by Samuel Martin in one of the three main strands of his "Sino-Xenic" (1953) nomenclature for Chinese as spoken and written in Vietnam (Sino-Vietnamese), Korea (Sino-Korean), and Japan (Sino-Japanese).
As a result of a thousand years of Chinese control, and a further thousand years of strong Chinese influence, a lot of Chinese vocabulary was adopted into Vietnamese. Literary Chinese was used in administration, and thus terms relating to science, politics, education, and philosophy entered the common lexicon. Like Sino-Korean and Sino-Japanese, these terms are pronounced differently in Vietnamese. Over the years, a system establishing rules on how to pronounce Chinese characters was developed.
As contact with the West grew, Western concepts were taken into Vietnamese through the filter of Chinese. Western works were translated into Chinese and read by the literati. Western names, approximated in Chinese (in some cases approximated in Japanese and then borrowed into Chinese), were further garbled in Vietnamese pronunciations. For example, Portugal became 葡萄牙, and in Vietnamese Bồ Đào Nha. England became Anh Cát Lợi (英吉利) shortened to Anh (英), while America became Mỹ Lợi Gia (美利加), shortened to Mỹ (美). Interestingly, club became 俱樂部 kurabu in Japan, was borrowed to China, then to Vietnam, is read as câu lạc bộ, and abbreviated CLB, which can be an abbreviation for club.
Recently, Sino-Vietnamese has been playing a less important role in Vietnamese as efforts are made to use native Vietnamese words or phonetic pronunciations of certain foreign words in cases where Sino-Vietnamese is considered pointless or simply an elaborate form of phoneticizing. Wherever there exists adequate native Vietnamese terminology, native terms will tend to be used. For example, the White House is referred to as Nhà Trắng, as opposed to the austere-sounding Bạch Ốc (白屋).
Another example is the Vietnamese name of countries; except for the most deeply ingrained, or ones with Chinese references (e.g. "Trung Quốc" for China), Vietnamese names for countries of the world are now close to their original spelling or pronunciation instead of Sino-Vietnamese. This practice of naming countries is similar to other sinoxenic languages such as Japanese and Korean. However, China-specific names and concepts (toponyms or political, literary, religious, scientific, medical, and technical terminology) continue to be rendered in Sino-Vietnamese.
Sometimes regional variation can be found in the prevalence of a Sino-Vietnamese or native term. For example, máy bay is the standard (Hanoi) word for an aeroplane; in the south, phi cơ (from 飛機) is more common but losing popularity.
Sino-Vietnamese vocabulary has a status similar to that of Latin-based words in English: they are used more in formal context than in everyday life. Because Chinese and Vietnamese use different order for subject and modifier, compound Sino-Vietnamese words or phrases might appear ungrammatical in Vietnamese sentences. For example, the Sino-Vietnamese phrase bạch mã (白馬 - white horse) can be expressed in Vietnamese as ngựa trắng (horse white). For this reason, compound words containing native Vietnamese and Sino-Vietnamese words are very rare and are considered improper by some (for example, chung cư "apartment building" was originally derived from chúng cư 眾居 "multiple dwelling", but with the syllable chúng "multiple" replaced with chung, a pure Vietnamese word meaning "shared" or "together". These tend to only happen with "native" words with the same etymology as their Sino-Vietnamese counterparts.).
Some Sino-Vietnamese words are entirely invented by the Vietnamese and are not used in Chinese, such as linh mục (靈牧 - spiritual shepherd) for pastor. Others are no longer used in modern Chinese or have other meanings. For example, the Vietnamese word lý thuyết, meaning 'theory', is from the Chinese word 理説, which is no longer in use. The official name for the United States in Vietnamese is Hoa Kỳ (花旗). This is a former Chinese name of the United States and translates literally as "flower flag".
Writing Sino-Vietnamese words with quốc ngữ had caused some confusions about the origins of some terms, due to the large amount of homophones in Chinese and Sino-Vietnamese. For example, both 明 (bright) and 冥 (dark) are read as minh, thus the word "minh" has two contradictory meanings: bright and dark (although the "dark" meaning is now esoteric and is used in only a few compound words). Perhaps for this reason, the Vietnamese name for Pluto isn't Minh Vương Tinh (冥王星 - lit. underworld king star) as in other East Asian languages, but is Diêm Vương Tinh (閻王星), named after the Hindu and Buddhist deity Yama. During the Hồ Dynasty, Vietnam was officially known as Đại Ngu (大虞 - Great Peace). Unfortunately, most modern Vietnamese know ngu as "stupid" (愚); consequently, some misinterpret it as "Big Idiot" (大愚). Conversely, the Han River in South Korea is often erroneously translated as sông Hàn (韓) when it should be sông Hán (漢) due to the name's similarity with the country name. However, the homograph/homophone problem is not as serious as it appears, because although many Sino-Vietnamese words have multiple meanings when written with quốc ngữ, usually only one has widespread usage, while the others are relegated to obscurity. Furthermore, Sino-Vietnamese words are usually not used alone, but in compound words, thus the meaning of the compound word is preserved even if individually each has multiple meanings. Most importantly, since quốc ngữ is an exact phonetic transcription of the spoken language, its understandability is as high as or higher than a normal conversation.
In addition, quốc ngữ is sometimes used by ethnic Hoa who have forgotten how to use Chinese characters correctly, to communicate to other Hoa in Chinese; their spoken dialects are usually Cantonese or Teochew, which are close to Sino-Vietnamese. Thus, Sino-Vietnamese can actually be used as a fully functional written language.
See also 
- Chữ Nôm - the vernacular script
- Chữ Hán - Chinese written in Vietnam
- Sinoxenic - use of Chinese in Vietnam, Korea and Japan
- Wm C. Hannas (1997). Asia's orthographic dilemma. University of Hawaii Press. p. 77.
- Alves, Mark J. 2001. "What's So Chinese About Vietnamese?" In Papers from the Ninth Annual Meeting of the Southeast Asian Linguistics Society, edited by Graham W. Thurgood. 221-242. Arizona State University, Program for Southeast Asian Studies. PDF
- Alves, Mark J. 2007. “Categories of Grammatical Sino-Vietnamese Vocabulary” in Mon-Khmer Studies Volume 37, 217-229. PDF
- Alves, Mark J. 2009. “Loanwords in Vietnamese” in Loanwords in the World's Languages: A Comparative Handbook, ed. Martin Haspelmath and Uri Tadmor. 617-637. De Gruyter Mouton.
- Hannas, William C. 1997. Asia's Orthographic Dilemma. University of Hawaii Press.