The Vietnamese alphabet (Vietnamese: chữ Quốc ngữ; literally national language script) is the modern writing system for the Vietnamese language. It uses the Latin script, based on its employment in the alphabets of Romance languages, in particular the Portuguese alphabet, with some digraphs and the addition of nine accent marks or diacritics – four of them to create additional sounds, and the other five to indicate the tone of each word. The many diacritics, often two on the same letter, make written Vietnamese easily recognizable.
- 1 Letter names and pronunciation
- 2 Consonants
- 3 Vowels
- 4 Tone marks
- 5 Structure
- 6 History
- 7 Sino-Vietnamese and quốc ngữ
- 8 Computer support
- 9 See also
- 10 Bibliography
- 11 Further reading
- 12 References
- 13 External links
Letter names and pronunciation
|B b||bê; bờ||/ɓe˧, ɓəː˧˩/|
|C c||xê; cờ||/se˧, kəː˧˩/|
|D d||dê; dờ||/ze˧, zəː˧˩/|
|Đ đ||đê; đờ||/ɗe˧, ɗəː˧˩/|
|G g||giê; gờ; ghê||/ze˧, ɣəː˧˩, ɣe˧/|
|H h||hắt; hờ||/hat˦˥, həː˧˩/|
|I i||i; i ngắn||/i˧, i˧ ŋan˧˥/|
|K k||ca; kờ||/kaː˧/|
|L l||e-lờ; lờ||/(ɛ˧)ləː˧˩/|
|M m||em-mờ; mờ||/(ɛm˧)məː˧˩/|
|N n||en-nờ; nờ||/(ɛn˧)nəː˧˩/|
|P p||pê; pờ; bê phở (colloq.)||/pe˧, pəː˧˩/|
|Q q||cu; quy; quờ||/ku˧, kwi˧, kwəː˧˩/|
|R r||e-rờ; rờ||/ɛ˧ɹəː˧˩, ʐəː˧˩/|
|S s||ét-xì; sờ; xờ mạnh; xờ nặng||/ɛt˦˥si˧˩, ʂəː˧˩/|
|T t||tê; tờ||/te˧, təː˧˩/|
|V v||vê, vờ||/ve˧, vəː˧/|
|X x||ích xì||/ik˦˥si˧˩, səː˧˩/|
|Y y||i dài; i-cờ-rét||/i˧zaːj˧˩, i˧kəː˧ɹɛt˦˥/|
Note: Naming b 'bê bò' and p 'bê phở' is to avoid confusion in some dialects or some contexts, the same for s 'xờ mạnh (nặng)' and x 'xờ nhẹ', i 'i ngắn' and y 'i dài'. Q, q is always followed by u in every word and phrase in Vietnamese, e.g. quang (light), quần (trousers), quyến rũ (to attract), etc.
|d||/z/||/j/||In Middle Vietnamese, ⟨d⟩ was pronounced [ð].|
|gh||/ɣ/||Used before ⟨i e ê⟩ to avoid confusion with ⟨gi⟩|
|gi||/z/||/j/||In Middle Vietnamese, ⟨gi⟩ was pronounced [ʝ].|
|ngh||/ŋ/||Used before ⟨i e ê⟩ to avoid confusion with ⟨gi⟩|
|p||/p/||Does not occur initially in native vocabulary|
|ph||/f/||In Middle Vietnamese, ⟨ph⟩ was pronounced [pʰ]|
|r||/z/ or /ɹ/ (only in loan words)||/ɹ or ʐ/|
|s||/s/||/ʂ/ or /s/ (informal)||In Middle Vietnamese, ⟨s⟩ was pronounced [ʂ].|
|tr||/c/||/ʈ͡ʂ/ or /c/ (informal)|
|v||/v/||/v/ or /j/ (informal)||In Middle Vietnamese, it was represented by ⟨ꞗ⟩ and was pronounced [β].|
|x||/s/||In Middle Vietnamese, ⟨x⟩ was pronounced [ɕ].|
The correspondence between the orthography and pronunciation is somewhat complicated. In some cases, the same letter may represent several different sounds, and different letters may represent the same sound. This may be because the orthography was designed centuries ago and the spoken language has changed, or because the inventors were trying to spell the sounds of several dialects at once.
The letters y and i are mostly equivalent, and there is no concrete rule that says when to use one or the other, except in diphthongs like ay and uy (i.e. tay ("arm, hand") is read /tɐj/ while tai ("ear") is read /taːj/). There have been attempts since the early 20th century to standardize the orthography by replacing all the vowel uses of y with i, the latest being a decision from the Vietnamese Ministry of Education in 1984. These efforts seem to have had limited effect, in part because some people bristled at the thought of names such as Nguyễn becoming Nguiễn and Thúy (a common female name) becoming Thúi (stinky), even though the standardization does not apply to diphthongs and triphthongs and allowed exceptions to proper names. In textbooks published by Nhà Xuất bản Giáo dục ("Publishing House of Education"), y is used to represent /i/ only in Sino-Vietnamese words that are written with one letter y alone (diacritics can still be added, as in ý, ỷ), in words that start with the letter y (such as yếm, yết), and after u; therefore such forms as *lý and *kỹ are not "standard", though they are much preferred elsewhere. Most people and the popular media continue to use the spelling that they are most accustomed to.
Spelling Sound Spelling Sound a /aː/, [æ] in some dialects, /a/ before "u" and "y", /ə/ in "ia" /iə/ o /ɔ/, /aw/ before "ng" and "c"; /w/ before "a", "ă" and "e" ă /a/ ô /o/, /əw/ before "ng" and "c" except "uông" and "uôc" â /ə/ ơ /əː/ e /ɛ/ u /u/, /w/ ê /e/, /ə/ after i (iê) ư /ɨ/
The uses of the letters i and y to represent the phoneme /i/ can be categorized as "standard" (as used in textbooks published by Nhà Xuất bản Giáo dục) and "non-standard" as follows.
Context "Standard" "Non-standard" In one-lettered non-Sino-Vietnamese syllables i (eg: i tờ, í ới, ì ạch, ỉ ôi, đi ị) In one-lettered Sino-Vietnamese syllables y (eg: y học, ý kiến, ỷ lại) Syllable-initial, not followed by ê i (eg: ỉa đái, im lặng, ích lợi, ỉu xìu) Syllable-initial, followed by ê y (eg: yếu ớt, yếm dãi, yết hầu) After u y (eg: uy lực, huy hoàng, khuya khoắt, tuyển mộ, khuyết tật, khuỷu tay, huýt sáo, khuynh hướng) After qu, not followed by ê, nh y (eg: quý giá, quấn quýt) i (eg: quí giá, quấn quít) After qu, followed by ê, nh y (eg: quyên góp, xảo quyệt, mừng quýnh, hoa quỳnh) After b, d, đ, r, x i (eg: bịa đặt, diêm dúa, địch thủ, rủ rỉ, triều đại, xinh xắn) After g, not followed by a, ă, â, e, ê, o, ô, ơ, u, ư i (eg: cái gì?, giữ gìn) After h, k, l, m, t, not followed by any letter, in non-Sino-Vietnamese syllables i (eg: ti hí, kì cọ, lí nhí, mí mắt, tí xíu) After h, k, l, m, t, not followed by any letter, in Sino-Vietnamese syllables i (eg: hi vọng, kì thú, lí luận, mĩ thuật, giờ Tí) y (eg: hy vọng, kỳ thú, lý luận, mỹ thuật, giờ Tý) After ch, gh, kh, nh, ph, th i (eg: chíp hôi, ghi nhớ, ý nghĩa, khiêu khích, nhí nhố, phiến đá, buồn thiu) After n, s, v, not followed by any letter, in non-proper-noun syllables i (eg: ni cô, si tình, vi khuẩn) After n, s, v, not followed by any letter, in proper nouns i (eg: Ni, Thuỵ Sĩ, Vi) y (eg: Ny, Thụy Sỹ, Vy) After h, k, l, m, n, s, t, v, followed by a letter i (eg: thương hiệu, kiên trì, bại liệt, ngôi miếu, nũng nịu, siêu đẳng, mẫn tiệp, được việc) In Vietnamese personal names, after a consonant i either i or y, depending on personal preference
The table below matches the vowels of Hanoi Vietnamese (written in the IPA) and their respective orthographic symbols used in the writing system.
Front Central Back Sound Spelling Sound Spelling Sound Spelling Close /i/ i, y /ɨ/ ư /u/ u Close-mid /e/ ê /əː/ ơ /o/ ô Open-mid /ɛ/ e /ə/ â /ɔ/ o Open /aː/ a /a/ ă
- The vowel /i/ is:
- usually written i: /si/ = sĩ (A suffix indicating profession, similar to the English suffix -er).
- sometimes written y after h, k, l, m, s, t, v: /mi/ = Mỹ 'America'.
- It is always written y when:
- preceded by an orthographic vowel: /xwiən/ = khuyên 'to advise';
- at the beginning of a word derived from Chinese (written as i otherwise): /ʔiəw/ = yêu 'to love'.
- The vowel /ɔ/ is written oo before c or ng (since o in that position represents /aw/): /ʔɔk/ = oóc 'organ (musical)'; /kiŋ kɔŋ/ = kính coong. This generally only occurs in recent loanwords or when representing dialectal pronunciation.
- Similarly, the vowel /o/ is written ôô before c or ng: /ʔoŋ/ = ôông (dialectal variant of ông /ʔəwŋ/).
Diphthongs and triphthongs
Sound Spelling Sound Spelling Diphthongs /uj/ ui /iw/ iu /oj/ ôi /ew/ êu /ɔj/ oi /ɛw/ eo /əːj/ ơi /əj/ ây, ê in ⟨ênh⟩ /əjŋ/ and ⟨êch⟩ /əjk/ /əw/ âu, ô in ⟨ông⟩ /əwŋ/ and ⟨ôc⟩ /əwk/ /aːj/ ai /aːw/ ao /aj/ ay, a in ⟨anh⟩ /ajŋ/ and ⟨ach⟩ /ajk/ /aw/ au, o in ⟨onɡ⟩ /awŋ/ and ⟨oc⟩ /awk/ /ɨj/ ưi /ɨw/, northern usually /iw/ ưu /iə/ ia, ya, iê, yê /uə/ ua, uô /ɨə/ ưa, ươ /wi/ uy Triphthongs /iəw/ iêu, yêu /uəj/ uôi /ɨəj/ ươi /ɨəw/, northern usually /iəw/ ươu
The diphthong /iə/ is written:
- ia in open syllables: /miə/ = mía 'sugar cane' (note: open syllables end with a vowel; closed syllables end with a consonant);
- iê before a consonant: /miəŋ/ = miếng 'piece';
The i changes to y at the beginning of words or after an orthographic vowel:
- ya: /xwiə/ = khuya 'late at night'
- yê: /xwiən/ = khuyên 'to advise'; /iən/ = yên 'calm'.
The diphthong /uə/ is written:
- ua in open syllables: /muə/ = mua 'to buy';
- uô before a consonant: /muən/ = muôn 'ten thousand'.
The diphthong /ɨə/ is written:
- ưa in open syllables: /mɨə/ = mưa 'to rain';
- ươ before consonants: /mɨəŋ/ = mương 'irrigation canal'.
Vietnamese is a tonal language, i.e., the meaning of each word depends on the "tone" (basically a specific tone and glottalization pattern) in which it is pronounced. There are six distinct tones in the standard northern dialect. In the south, there is a merging of the hỏi and ngã tones, in effect leaving five basic tones. The first one ("level tone") is not marked, and the other five are indicated by diacritics applied to the vowel part of the syllable. The tone names are chosen such that the name of each tone is spoken in the tone it identifies.
|Name||Contour||Diacritic||Vowels with diacritic|
|Ngang or Bằng||mid level, ˧||unmarked||A/a, Ă/ă, Â/â, E/e, Ê/ê, I/i, O/o, Ô/ô, Ơ/ơ, U/u, Ư/ư, Y/y|
|Huyền||low falling, ˨˩||grave accent||À/à, Ằ/ằ, Ầ/ầ, È/è, Ề/ề, Ì/ì, Ò/ò, Ồ/ồ, Ờ/ờ, Ù/ù, Ừ/ừ, Ỳ/ỳ|
|Hỏi||mid falling, ˧˩ (Northern); dipping, ˨˩˥ (Southern)||hook above||Ả/ả, Ẳ/ẳ, Ẩ/ẩ, Ẻ/ẻ, Ể/ể, Ỉ/ỉ, Ỏ/ỏ, Ổ/ổ, Ở/ở, Ủ/ủ, Ử/ử, Ỷ/ỷ|
|Ngã||glottalized rising, ˧˥ˀ (Northern); dipping, ˨˩˥ (Southern)||tilde||Ã/ã, Ẵ/ẵ, Ẫ/ẫ, Ẽ/ẽ, Ễ/ễ, Ĩ/ĩ, Õ/õ, Ỗ/ỗ, Ỡ/ỡ, Ũ/ũ, Ữ/ữ, Ỹ/ỹ|
|Sắc||high rising, ˧˥||acute accent||Á/á, Ắ/ắ, Ấ/ấ, É/é, Ế/ế, Í/í, Ó/ó, Ố/ố, Ớ/ớ, Ú/ú, Ứ/ứ, Ý/ý|
|Nặng||glottalized falling, ˧˨ˀ (Northern); low rising, ˩˧ (Southern)||dot below||Ạ/ạ, Ặ/ặ, Ậ/ậ, Ẹ/ẹ, Ệ/ệ, Ị/ị, Ọ/ọ, Ộ/ộ, Ợ/ợ, Ụ/ụ, Ự/ự, Ỵ/ỵ|
- Unmarked vowels are pronounced with a level voice, in the middle of the speaking range.
- The grave accent indicates that the speaker should start somewhat low and drop slightly in tone, with the voice becoming increasingly breathy.
- The hook indicates that the speaker should start somewhat low, and fall in Northern Vietnamese, but the speaker should start somewhat low, and fall, then rise (as when asking a question in English) in Southern Vietnamese.
- A tilde indicates that the speaker should start mid, break off (with a glottal stop), then start again and rise like a question in tone.
- The acute accent indicates that the speaker should start mid and rise sharply in tone.
- The dot signifies that the speaker should start low and fall lower in tone, with the voice becoming increasingly creaky and ending in a glottal stop in Northern Vietnamese, but Southern speakers starts low and rise mid in tone.
In syllables where the vowel part consists of more than one vowel (such as diphthongs and triphthongs), the placement of the tone is still a matter of debate. Generally, there are two methodologies, an "old style" and a "new style". While the "old style" emphasizes aesthetics by placing the tone mark as close as possible to the center of the word (by placing the tone mark on the last vowel if an ending consonant part exists and on the next-to-last vowel if the ending consonant doesn't exist, as in hóa, hủy), the "new style" emphasizes linguistic principles and tries to apply the tone mark on the main vowel (as in hoá, huỷ). In both styles, when one vowel already has a quality diacritic on it, the tone mark must be applied to it as well, regardless of where it appears in the syllable (thus thuế is acceptable while thúê is not). In the case of the ươ diphthong, the mark is placed on the ơ. The u in qu is considered part of the consonant. Currently, the new style is usually used in textbooks published by Nhà Xuất bản Giáo dục, while most people still prefer the old style in casual uses.
In lexical ordering, differences in letters are treated as primary, differences in tone markings as secondary, and differences in case as tertiary differences. Ordering according to primary and secondary differences proceeds syllable by syllable. According to this principle, a dictionary lists tuân thủ before tuần chay because the secondary difference in the first syllable takes precedence over the primary difference in the second.
As a result of influence from the Chinese writing system, each syllable in Vietnamese is written separately as if it were a word. In the past, syllables in multisyllabic words were concatenated with hyphens, but this practice had died out, and hyphenation is now reserved for foreign borrowings. A written syllable consists of at most three parts, in the following order from left to right:
- An optional beginning consonant part
- A required vowel syllable nucleus and the tone mark, if needed, applied above or below it
- An optional ending consonant part, can only be one of the following: c, ch, m, n, ng, nh, p, t, or nothing.
The Vietnamese language was first written down, from the 13th century onwards, using variant Chinese characters (chữ nôm 字喃), each of them representing one word. The system was based on the script used for writing classical Chinese (chữ nho), but it was supplemented with characters developed in Vietnam (chữ thuần nôm, proper Nom characters) to represent native Vietnamese words.
As early as 1527, Portuguese Catholic missionaries in Vietnam began using Latin script to transcribe the Vietnamese language for teaching and evangelization purposes. These informal efforts led eventually to the development of the present Vietnamese alphabet, largely by the work of French Jesuit Alexandre de Rhodes, who worked in the country between 1624 and 1644. Building on previous Portuguese–Vietnamese dictionaries by Gaspar d'Amaral and fellow Jesuit Duarte da Costa, Rhodes wrote the Dictionarium Annamiticum Lusitanum et Latinum, a Vietnamese–Portuguese–Latin dictionary, which was printed in Rome in 1651, using his spelling system.
In spite of this development, chữ nôm and chữ nho remained dominant until the early 20th century. The Tonkin Free School, set up by nationalists in 1907, taught alphabetic script. Primary schools in Tonkin began teaching the script in 1910, and Emperor Khải Định declared the traditional writing system abolished in 1918. By the 1930s, alphabetic script was Vietnam's dominant writing system. Despite conflicts over the meaning of Vietnamese nationalism during the Vietnam War, as both sides sought to define themselves as the true national government, neither side attempted to promote a new and separate writing system or revert to Chinese characters.
Because the period of education necessary to gain initial literacy is considerably less for the largely phonetic Latin-based script compared to the several years necessary to master the full range of Chinese characters, the adoption of the Vietnamese alphabet also facilitated widespread literacy among Vietnamese speakers— whereas a majority of Vietnamese in Vietnam could not read or write prior to the 20th century, the population is now almost universally literate.
Historian Pamela A. Pears asserted that the French, by instituting the Roman alphabet in Vietnam, cut the Vietnamese off from their traditional literature, rendering them unable to read it. The current Vietnamese government has recognised this as a problem, and supported the publication of inexpensive transliterated editions of some older and more obscure Vietnamese literature.
Prior to the advent of 21st-century computer-assisted typesetting methods, the act of typesetting and printing Vietnamese had been described as a "nightmare" due to the number of accents and diacritics.
Sino-Vietnamese and quốc ngữ
Writing Sino-Vietnamese words with quốc ngữ caused some confusion about the origins of some terms, due to the large number of homophones in Chinese and Sino-Vietnamese. For example, both 明 (bright) and 冥 (dark) are read as minh, which therefore has two opposite meanings (although the meaning of "dark" is now esoteric and is used in only a few compound words). Perhaps for this reason, the Vietnamese name for Pluto is not 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 Buddhist deity Yama. During the Hồ Dynasty, Vietnam was officially known as Đại Ngu (大虞 – Great Yu). Most modern Vietnamese know ngu as "stupid" (愚); consequently, some misinterpret it as "Big Idiot". In this case, "Ngu" means peace and joy. However, the homograph/homophone problem is not as serious as it may seem, 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 phonemic transcription of the spoken language, its understandability is as high or higher than a normal conversation.
The Vietnamese keyboard layout is an extended Latin QWERTY layout. The letters Ă, Â, Ê, and Ô are found on what would be the number keys 1–4 on the American English keyboard, with 5–9 producing the tonal marks (grave accent, hook, tilde, acute accent, and dot below, in that order), 0 producing Đ, = producing the đồng sign (₫) when not shifted, and brackets () producing Ư and Ơ.
The universal character set Unicode has full support for the Vietnamese writing system, although it does not have a separate segment for it. The required characters that other languages use are scattered throughout the Basic Latin, Latin-1 Supplement, Latin Extended-A, and Latin Extended-B blocks; those that remain (such as the letters with more than one diacritic) are placed in the Latin Extended Additional block. An ASCII-based writing convention, Vietnamese Quoted Readable, and several byte-based encodings including TCVN3, VNI, and VISCII were widely used before Unicode became popular. Most new documents now exclusively use the Unicode format UTF-8.
Unicode allows the user to choose between precomposed characters and combining characters in inputting Vietnamese. Because, in the past some fonts implemented combining characters in a nonstandard way (see Verdana font), most people use precomposed characters when composing Vietnamese-language documents.
Most keyboards used by Vietnamese-language users do not support direct input of diacritics by default. Various free utilities that act as keyboard drivers exist. They support the most popular input methods, including Telex, VIQR and its variants, and VNI.
- Chữ nôm, formerly the script used to write the Vietnamese language.
- Vietnamese Braille
- Ă, Â, Đ, Ê, Ô, Ơ, Ư
- Dot (diacritic)
- Hook above
- Horn (diacritic)
- VIQR, a standard 7-bit writing convention of the Vietnamese alphabet.
- VISCII, a standard 8-bit encoding of the Vietnamese alphabet.
- Vietnamese phonology
- Vietnamese calligraphy
- Gregerson, Kenneth J. (1969). A study of Middle Vietnamese phonology. Bulletin de la Société des Etudes Indochinoises, 44, 135-193. (Published version of the author's MA thesis, University of Washington). (Reprinted 1981, Dallas: Summer Institute of Linguistics).
- Haudricourt, André-Georges (1949). "Origine des particularités de l'alphabet vietnamien (English translation as: The origin of the peculiarities of the Vietnamese alphabet)". Dân Việt-Nam 3: 61–68.
- Healy, Dana.(2003). Teach Yourself Vietnamese, Hodder Education, London.
- Nguyen, Đang Liêm. (1970). Vietnamese pronunciation. PALI language texts: Southeast Asia. Honolulu: University of Hawaii Press. ISBN 0-87022-462-X
- Nguyễn, Đình-Hoà. (1955). Quốc-ngữ: The modern writing system in Vietnam. Washington, D. C.: Author.
- Nguyễn, Đình-Hoà (1992). "Vietnamese phonology and graphemic borrowings from Chinese: The Book of 3,000 Characters revisited". Mon-Khmer Studies 20: 163–182.
- Nguyễn, Đình-Hoà. (1996). Vietnamese. In P. T. Daniels, & W. Bright (Eds.), The world's writing systems, (pp. 691–699). New York: Oxford University Press. ISBN 0-19-507993-0.
- Nguyễn, Đình-Hoà. (1997). Vietnamese: Tiếng Việt không son phấn. Amsterdam: John Benjamins Publishing Company. ISBN 1-55619-733-0.
- Pham, Andrea Hoa. (2003). Vietnamese tone: A new analysis. Outstanding dissertations in linguistics. New York: Routledge. (Published version of author's 2001 PhD dissertation, University of Florida: Hoa, Pham. Vietnamese tone: Tone is not pitch). ISBN 0-415-96762-7.
- Sassoon, Rosemary (1995). The Acquisition of a Second Writing System (illustrated, reprint ed.). Intellect Books. ISBN 1871516439. Retrieved 24 April 2014.
- Thompson, Laurence E. (1991). A Vietnamese reference grammar. Seattle: University of Washington Press. Honolulu: University of Hawaii Press. ISBN 0-8248-1117-8. (Original work published 1965).
- Wellisch, Hans H. (1978). The conversion of scripts, its nature, history, and utilization. Information sciences series (illustrated ed.). Wiley. ISBN 0471016209. Retrieved 24 April 2014.
- Language Monthly, Issues 40-57. Praetorius. 1987. Retrieved 24 April 2014.
- Nguyen, A. M. (2006). Let's learn the Vietnamese alphabet. Las Vegas: Viet Baby. ISBN 0-9776482-0-6
- Shih, Virginia Jing-yi. Quoc Ngu Revolution: A Weapon of Nationalism in Vietnam. 1991.
- Haudricourt, André-Georges. 2010. “The Origin of the Peculiarities of the Vietnamese Alphabet.” Mon-Khmer Studies 39: 89–104. Translated from: Haudricourt, André-Georges. 1949. “L’origine Des Particularités de L’alphabet Vietnamien.” Dân Viêt-Nam 3: 61–68.
- Roland Jacques (2002). Portuguese pioneers of Vietnamese linguistics prior to 1650. Orchid Press.
- Jakob Rupert Friederichsen Opening Up Knowledge Production Through Participatory Research? Frankfurt 2009 [6.1 History of Science and Research in Vietnam] Page 126 "6.1.2 French colonial science in Vietnam: With the colonial era, deep changes took place in education, communication, and ... French colonizers installed a modern European system of education to replace the literary and Confucianism-based model, they promoted a romanized Vietnamese script (Quốc Ngữ) to replace the Sino-Vietnamese characters (Hán Nôm)"
- Pamela A. Pears (2006). Remnants of Empire in Algeria and Vietnam: Women, Words, and War. Lexington Books. p. 18. ISBN 0-7391-2022-0. Retrieved 2010-11-28.
- Wellisch 1978, p. 94.
- "Language Monthly, Issues 40-57" 1987, p. 20.
- Sassoon 1995, p. 123.