Vietnamese language

The following diagram shows the phonology of Proto–Viet–Muong (the nearest ancestor of Vietnamese and the closely related Muong language), along with the outcomes in the modern language:[19][20][21][22]

		Labial	Dental/Alveolar		Palatal	Velar	Glottal
Stop	tenuis	*p > b	*t > đ		*c > ch	*k > k/c/q	*ʔ > #
	voiced	*b > b	*d > đ		*ɟ > ch	*ɡ > k/c/q
	aspirated	*pʰ > ph	*tʰ > th			*kʰ > kh
	implosive	*ɓ > m	*ɗ > n		*ʄ > nh 1
Nasal		*m > m	*n > n		*ɲ > nh	*ŋ > ng/ngh
Affricate					*tʃ > x 1
Fricative	voiceless			*s > t			*h > h
	voiced 2	*(β) > v 3	*(ð) > d	*(r̝) > r 4	*(ʝ) > gi	*(ɣ) > g/gh
Approximant		*w > v	*l > l	*r > r	*j > d

^1 According to Ferlus, */tʃ/ and */ʄ/ are not accepted by all researchers. Ferlus 1992[19] also had additional phonemes */dʒ/ and */ɕ/.

^2 The fricatives indicated above in parentheses developed as allophones of stop consonants occurring between vowels (i.e. when a minor syllable occurred). These fricatives were not present in Proto-Viet–Muong, as indicated by their absence in Muong, but were evidently present in the later Proto-Vietnamese stage. Subsequent loss of the minor-syllable prefixes phonemicized the fricatives. Ferlus 1992[19] proposes that originally there were both voiced and voiceless fricatives, corresponding to original voiced or voiceless stops, but Ferlus 2009[20] appears to have abandoned that hypothesis, suggesting that stops were softened and voiced at approximately the same time, according to the following pattern:

• *p, *b > /β/
• *t, *d > /ð/
• *s > /r̝/
• *c, *ɟ, *tʃ > /ʝ/
• *k, *ɡ > /ɣ/

^3 In Middle Vietnamese, the outcome of these sounds was written with a hooked b (ꞗ), representing a /β/ that was still distinct from v (then pronounced /w/). See below.

^4 It is unclear what this sound was. According to Ferlus 1992,[19] in the Archaic Vietnamese period (c. 10th century AD, when Sino-Vietnamese vocabulary was borrowed) it was *r̝, distinct at that time from *r.

The following initial clusters occurred, with outcomes indicated:

• *pr, *br, *tr, *dr, *kr, *gr > /kʰr/ > /kʂ/ > s
• *pl, *bl > MV bl > Northern gi, Southern tr
• *kl, *gl > MV tl > tr
• *ml > MV ml > mnh > nh
• *kj > gi

A large number of words were borrowed from Middle Chinese, forming part of the Sino-Vietnamese vocabulary. These caused the original introduction of the retroflex sounds /ʂ/ and /ʈ/ (modern s, tr) into the language.

Proto-Viet–Muong had no tones to speak of. The tones later developed in some of the daughter languages from distinctions in the initial and final consonants. Vietnamese tones developed as follows:[23]

Register	Initial consonant	Smooth ending	Glottal ending	Fricative ending
High (first) register	Voiceless	A1 ngang "level"	B1 sắc "sharp"	C1 hỏi "asking"
Low (second) register	Voiced	A2 huyền "deep"	B2 nặng "heavy"	C2 ngã "tumbling"

Glottal-ending syllables ended with a glottal stop /ʔ/, while fricative-ending syllables ended with /s/ or /h/. Both types of syllables could co-occur with a resonant (e.g. /m/ or /n/).

At some point, a tone split occurred, as in many other mainland Southeast Asian languages. Essentially, an allophonic distinction developed in the tones, whereby the tones in syllables with voiced initials were pronounced differently from those with voiceless initials. (Approximately speaking, the voiced allotones were pronounced with additional breathy voice or creaky voice and with lowered pitch. The quality difference predominates in today's northern varieties, e.g. in Hanoi, while in the southern varieties the pitch difference predominates, as in Ho Chi Minh City.) Subsequent to this, the plain-voiced stops became voiceless and the allotones became new phonemic tones. Note that the implosive stops were unaffected, and in fact developed tonally as if they were unvoiced. (This behavior is common to all East Asian languages with implosive stops.)

As noted above, Proto-Viet–Muong had sesquisyllabic words with an initial minor syllable (in addition to, and independent of, initial clusters in the main syllable). When a minor syllable occurred, the main syllable's initial consonant was intervocalic and as a result suffered lenition, becoming a voiced fricative. The minor syllables were eventually lost, but not until the tone split had occurred. As a result, words in modern Vietnamese with voiced fricatives occur in all six tones, and the tonal register reflects the voicing of the minor-syllable prefix and not the voicing of the main-syllable stop in Proto-Viet–Muong that produced the fricative. For similar reasons, words beginning with /l/ and /ŋ/ occur in both registers. (Thompson 1976[22] reconstructed voiceless resonants to account for outcomes where resonants occur with a first-register tone, but this is no longer considered necessary, at least by Ferlus.)

Old Vietnamese Phonology[24]

		Labial	Alveolar	Palatal	Velar	Glottal
Nasal		m (m)	n (n)	nh (ɲ)	ng/ngh (ŋ)
Stop	tenuis	b/v ([p b])	d/đ ([t ɗ])	ch/gi (c)	c/k/q ([k ɡ])	# (ʔ)
	aspirated	ph (pʰ)	th (tʰ)	t/r (s)	kh (kʰ)	h (h)
	Implosive stop	m (ɓ)	n (ɗ)	nh (ʄ)
Fricative	voiced	v (v)		d (j)
Affricate				x (tʃ)
Liquid		r [r]	l [l]

Old Vietnamese/Ancient Vietnamese was a Vietic language which was separated from Viet–Muong around 9th century, and evolved to Middle Vietnamese by 16th century. The sources for the reconstruction of Old Vietnamese are Nom texts, such as the 12th-century/1486 Buddhist scripture Phật thuyết Đại báo phụ mẫu ân trọng kinh ("Sūtra explained by the Buddha on the Great Repayment of the Heavy Debt to Parents"),[25] old inscriptions, and late 13th-century (possibly 1293) Annan Jishi glossary by Chinese diplomat Chen Fu (c. 1259 – 1309).[26] Old Vietnamese used Chinese characters phonetically where each word, monosyllabic in Modern Vietnamese, is written with two Chinese characters or in a composite character made of two different characters.[27] It conveys the transformation of Vietnamese lexicons from sesquisyllabic to fully monosyllabic through monosyllabization process under pressures of Chinese linguistic influence, characterized by phenomena such as the reduction of minor syllables; loss of affixal morphology drifting towards analytical grammar; simplification of major syllable segments, and change of suprasegment instruments.[28]

For examples, the modern Vietnamese word "trời" (heaven) was read as *plời in Old/Ancient Vietnamese.

The writing system used for Vietnamese is based closely on the system developed by Alexandre de Rhodes for his 1651 Dictionarium Annamiticum Lusitanum et Latinum. It reflects the pronunciation of the Vietnamese of Hanoi at that time, a stage commonly termed Middle Vietnamese (tiếng Việt trung đại). The pronunciation of the "rime" of the syllable, i.e. all parts other than the initial consonant (optional /w/ glide, vowel nucleus, tone and final consonant), appears nearly identical between Middle Vietnamese and modern Hanoi pronunciation. On the other hand, the Middle Vietnamese pronunciation of the initial consonant differs greatly from all modern dialects, and in fact is significantly closer to the modern Saigon dialect than the modern Hanoi dialect.

The following diagram shows the orthography and pronunciation of Middle Vietnamese:

		Labial	Dental/ Alveolar	Retroflex	Palatal	Velar	Glottal
Nasal		m [m]	n [n]		nh [ɲ]	ng/ngh [ŋ]
Stop	tenuis	p [p]1	t [t]	tr [ʈ]	ch [c]	c/k [k]
	aspirated	ph [pʰ]	th [tʰ]			kh [kʰ]
	implosive	b [ɓ]	đ [ɗ]
Fricative	voiceless			s/ſ [ʂ]	x [ɕ]		h [h]
	voiced	ꞗ [β]2	d [ð]		gi [ʝ]	g/gh [ɣ]
Approximant		v/u/o [w]	l [l]		y/i/ĕ [j]3
Rhotic			r [r]

The first page of the ꞗ section in Alexandre de Rhodes's Dictionarium Annamiticum Lusitanum et Latinum (Vietnamese–Portuguese–Latin dictionary)

^1 [p] occurs only at the end of a syllable.
^2 This symbol, "Latin small letter B with flourish", looks like: . It has a rounded hook that starts halfway up the left side (where the top of the curved part of the b meets the vertical, straight part) and curves about 180 degrees counterclockwise, ending below the bottom-left corner.
^3 [j] does not occur at the beginning of a syllable, but can occur at the end of a syllable, where it is notated i or y (with the difference between the two often indicating differences in the quality or length of the preceding vowel), and after /ð/ and /β/, where it is notated ĕ. This ĕ, and the /j/ it notated, have disappeared from the modern language.

Note that b [ɓ] and p [p] never contrast in any position, suggesting that they are allophones.

The language also has three clusters at the beginning of syllables, which have since disappeared:

• tl /tl/ > modern tr
• bl /ɓl/ > modern gi (Northern), tr (Southern)
• ml /ml/ > mnh /mɲ/ > modern nh

Most of the unusual correspondences between spelling and modern pronunciation are explained by Middle Vietnamese. Note in particular:

• de Rhodes' system has two different b letters, a regular b and a "hooked" b in which the upper section of the curved part of the b extends leftward past the vertical bar and curls down again in a semicircle. This apparently represented a voiced bilabial fricative /β/. Within a century or so, both /β/ and /w/ had merged as /v/, spelled as v.
• de Rhodes' system has a second medial glide /j/ that is written ĕ and appears in some words with initial d and hooked b. These later disappear.
• đ /ɗ/ was (and still is) alveolar, whereas d /ð/ was dental. The choice of symbols was based on the dental rather than alveolar nature of /d/ and its allophone [ð] in Spanish and other Romance languages. The inconsistency with the symbols assigned to /ɓ/ vs. /β/ was based on the lack of any such place distinction between the two, with the result that the stop consonant /ɓ/ appeared more "normal" than the fricative /β/. In both cases, the implosive nature of the stops does not appear to have had any role in the choice of symbol.
• x was the alveolo-palatal fricative /ɕ/ rather than the dental /s/ of the modern language. In 17th-century Portuguese, the common language of the Jesuits, s was the apico-alveolar sibilant /s̺/ (as still in much of Spain and some parts of Portugal), while x was a palatoalveolar /ʃ/. The similarity of apicoalveolar /s̺/ to the Vietnamese retroflex /ʂ/ led to the assignment of s and x as above.

de Rhodes's entry for dĕóu᷄ shows distinct breves, acutes and apices.

De Rhodes's orthography also made use of an apex diacritic, as in o᷄ and u᷄, to indicate a final labial-velar nasal /ŋ͡m/, an allophone of /ŋ/ that is peculiar to the Hanoi dialect to the present day. This diacritic is often mistaken for a tilde in modern reproductions of early Vietnamese writing.

Vietnamese is the sole official and national language of Vietnam. It is the first language of the majority of the Vietnamese population, as well as a first or second language for the country's ethnic minority groups.[33]

In the Czech Republic, Vietnamese has been recognized as one of 14 minority languages, on the basis of communities that have resided in the country either traditionally or on a long-term basis. This status grants the Vietnamese community in the country a representative on the Government Council for Nationalities, an advisory body of the Czech Government for matters of policy towards national minorities and their members. It also grants the community the right to use Vietnamese with public authorities and in courts anywhere in the country.[34][35]

Vietnamese is increasingly being taught in schools and institutions outside of Vietnam, a large part which is contributed by its large diaspora. In countries with strongly established Vietnamese-speaking communities such as the United States, France, Australia, Canada, Germany, and the Czech Republic, Vietnamese language education largely serves as a cultural role to link descendants of Vietnamese immigrants to their ancestral culture. Meanwhile, in countries near Vietnam such as Cambodia, Laos, and Thailand, the increased role of Vietnamese in foreign language education is largely due to the recent recovery of the Vietnamese economy.[36][37]

Since the 1980s, Vietnamese language schools (trường Việt ngữ/ trường ngôn ngữ Tiếng Việt) have been established for youth in many Vietnamese-speaking communities around the world, notably in the United States.[38][39]

Similarly, since the late 1980s, the Vietnamese-German community has enlisted the support of city governments to bring Vietnamese into high school curriculum for the purpose of teaching and reminding Vietnamese German students of their mother-tongue. Furthermore, there has also been a number of Germans studying Vietnamese due to increased economic investments and business.[40][41]

Historic and stronger trade and diplomatic relations with Vietnam and a growing interest among the French Vietnamese population (one of France's most established non-European ethnic groups) of their ancestral culture have also led to an increasing number of institutions in France, including universities, to offer formal courses in the language.[42]

Vietnamese has a large number of vowels. Below is a vowel diagram of Vietnamese from Hanoi (including centering diphthongs):

	Front	Central	Back
Centering	ia/iê [iə̯]	ưa/ươ [ɨə̯]	ua/uô [uə̯]
Close	i/y [i]	ư [ɨ]	u [u]
Close-mid/ Mid	ê [e]	ơ [əː] â [ə]	ô [o]
Open-mid/ Open	e [ɛ]	a [aː] ă [a]	o [ɔ]

Front and central vowels (i, ê, e, ư, â, ơ, ă, a) are unrounded, whereas the back vowels (u, ô, o) are rounded. The vowels â [ə] and ă [a] are pronounced very short, much shorter than the other vowels. Thus, ơ and â are basically pronounced the same except that ơ [əː] is of normal length while â [ə] is short – the same applies to the vowels long a [aː] and short ă [a].[lower-alpha 2]

The centering diphthongs are formed with only the three high vowels (i, ư, u). They are generally spelled as ia, ưa, ua when they end a word and are spelled iê, ươ, uô, respectively, when they are followed by a consonant.

In addition to single vowels (or monophthongs) and centering diphthongs, Vietnamese has closing diphthongs[lower-alpha 3] and triphthongs. The closing diphthongs and triphthongs consist of a main vowel component followed by a shorter semivowel offglide /j/ or /w/.[lower-alpha 4] There are restrictions on the high offglides: /j/ cannot occur after a front vowel (i, ê, e) nucleus and /w/ cannot occur after a back vowel (u, ô, o) nucleus.[lower-alpha 5]

	/w/ offglide		/j/ offglide
	Front	Central		Back
Centering	iêu [iə̯w]	ươu [ɨə̯w]	ươi [ɨə̯j]	uôi [uə̯j]
Close	iu [iw]	ưu [ɨw]	ưi [ɨj]	ui [uj]
Close-mid/ Mid	êu [ew]	– âu[əw]	ơi [əːj] ây [əj]	ôi [oj]
Open-mid/ Open	eo [ɛw]	ao [aːw] au [aw]	ai [aːj] ay [aj]	oi [ɔj]

The correspondence between the orthography and pronunciation is complicated. For example, the offglide /j/ is usually written as i; however, it may also be represented with y. In addition, in the diphthongs [āj] and [āːj] the letters y and i also indicate the pronunciation of the main vowel: ay = ă + /j/, ai = a + /j/. Thus, tay "hand" is [tāj] while tai "ear" is [tāːj]. Similarly, u and o indicate different pronunciations of the main vowel: au = ă + /w/, ao = a + /w/. Thus, thau "brass" is [tʰāw] while thao "raw silk" is [tʰāːw].

The consonants that occur in Vietnamese are listed below in the Vietnamese orthography with the phonetic pronunciation to the right.

		Labial	Dental/ Alveolar	Retroflex	Palatal	Velar	Glottal
Nasal		m [m]	n [n]		nh [ɲ]	ng/ngh [ŋ]
Stop	tenuis	p [p]	t [t]	tr [ʈ]	ch [c]	c/k/q [k]
	aspirated		th [tʰ]
	implosive	b [ɓ]	đ [ɗ]
Fricative	voiceless	ph [f]	x [s]	s [ʂ~s]		kh [x~kʰ]	h [h]
	voiced	v [v]	d/gi [z~j]			g/gh [ɣ]
Approximant			l [l]		y/i [j]	u/o [w]
Rhotic			r [r]

Some consonant sounds are written with only one letter (like "p"), other consonant sounds are written with a digraph (like "ph"), and others are written with more than one letter or digraph (the velar stop is written variously as "c", "k", or "q").

Not all dialects of Vietnamese have the same consonant in a given word (although all dialects use the same spelling in the written language). See the language variation section for further elaboration.

Syllable-final orthographic ch and nh in Vietnamese has had different analyses. One analysis has final ch, nh as being phonemes /c/, /ɲ/ contrasting with syllable-final t, c /t/, /k/ and n, ng /n/, /ŋ/ and identifies final ch with the syllable-initial ch /c/. The other analysis has final ch and nh as predictable allophonic variants of the velar phonemes /k/ and /ŋ/ that occur after the upper front vowels i /i/ and ê /e/; although they also occur after a, but in such cases are believed to have resulted from an earlier e /ɛ/ which diphthongized to ai (cf. ach from aic, anh from aing). (See Vietnamese phonology: Analysis of final ch, nh for further details.)

Pitch contours and duration of the six Northern Vietnamese tones as spoken by a male speaker (not from Hanoi). Fundamental frequency is plotted over time. From Nguyễn & Edmondson (1998).

Each Vietnamese syllable is pronounced with one of six inherent tones,[lower-alpha 6] centered on the main vowel or group of vowels. Tones differ in:

• length (duration)
• pitch contour (i.e. pitch melody)
• pitch height
• phonation

Tone is indicated by diacritics written above or below the vowel (most of the tone diacritics appear above the vowel; however, the nặng tone dot diacritic goes below the vowel).[lower-alpha 7] The six tones in the northern varieties (including Hanoi), with their self-referential Vietnamese names, are:

Name	Description	Contour	Diacritic	Example	Sample vowel	Unicode
ngang   'level'	mid level	˧	(no mark)	ma  'ghost'	a
huyền   'deep'	low falling (often breathy)	˨˩	◌̀ (grave accent)	mà  'but'	à	U+0340 or U+0300
sắc   'sharp'	high rising	˧˥	◌́ (acute accent)	má  'cheek, mother (southern)'	á	U+0341 or U+0301
hỏi   'questioning'	mid dipping-rising	˧˩˧	◌̉ (hook above)	mả  'tomb, grave'	ả	U+0309
ngã   'tumbling'	creaky high breaking-rising	˧ˀ˦˥	◌̃ (tilde)	mã  'horse (Sino-Vietnamese), code'	ã	U+0342 or U+0303
nặng   'heavy'	creaky low falling constricted (short length)	˨˩ˀ	◌̣ (dot below)	mạ  'rice seedling'	ạ	U+0323

Other dialects of Vietnamese may have fewer tones (typically only five).

Tonal differences of three speakers as reported in Hwa-Froelich & Hodson (2002).[43] The curves represent temporal pitch variation while two sloped lines (//) indicates a glottal stop.

Tone	Northern dialect	Southern dialect	Central dialect
Ngang (a)
Huyền (à)
Sắc (á)
Hỏi (ả)
Ngã (ã)
Nặng (ạ)

In Vietnamese poetry, tones are classed into two groups: (tone pattern)

Words with tones belonging to a particular tone group must occur in certain positions within the poetic verse.

Vietnamese Catholics practice a distinctive style of prayer recitation called đọc kinh, in which each tone is assigned a specific note or sequence of notes.

Many early studies brainstormed Vietnamese language-origins to have been either Tai, Sino-Tibetan or Austroasiatic. Austroasiatic origins are so far the most tenable to date, with some of the oldest words in Vietnamese being Austroasiatic in origin.[44][45]

Old Nôm character for rice noodle soup "phở". The character 米 on the left means "rice" whilst the character on the right "頗" was used to indicate the sound of the word (phở).

Although Vietnamese roots are classified as Austroasiatic, Vietic and Viet-Muong, the result of language contact with Chinese heavily influenced the Vietnamese language, causing it to diverge from Viet-Muong into Vietnamese, which was seen to have split Vietnamese from Muong around the 10th to 11th century. For instance, the Vietnamese word quản lý, meaning management (noun) or manage (verb) is likely descended from the same word as guǎnlǐ (管理) in Chinese, kanri (管理, かんり) in Japanese, and gwanli (관리, 管理) in Korean. Instances of Chinese contact include the historical Nam Việt (aka Nanyue) as well as other periods of influences. Besides English and French which have made some contributions to Vietnamese language, Japanese loanwords into Vietnamese are also a more recently studied phenomenon.

Modern linguists describe modern Vietnamese having lost many Proto-Austroasiatic phonological and morphological features that original Vietnamese had.[46] The Chinese influence on Vietnamese corresponds to various periods when Vietnam was under Chinese rule, and subsequent influence after Vietnam became independent. Early linguists thought that this meant Vietnamese lexicon then received only two layers of Chinese words, one stemming from the period under actual Chinese rule and a second layer from afterwards. These words are grouped together as Sino-Vietnamese vocabulary.

However, according to linguist John Phan, “Annamese Middle Chinese” was already used and spoken in the Red River Valley by the 1st century CE, and its vocabulary significantly fused with the co-existing Proto-Viet-Muong language, the immediate ancestor of Vietnamese. He lists three major classes of Sino-Vietnamese borrowings:[47][48][49] Early Sino-Vietnamese (Han Dynasty (ca. 1st century CE) and Jin Dynasty (ca. 4th century CE), Late Sino-Vietnamese (Tang Dynasty), Recent Sino-Vietnamese (Ming Dynasty and afterwards)

Additionally, the French presence in Vietnam from 1777 to the Geneva Accords of 1954 resulted in significant influence from French into the Indochina region (Laos, Cambodia and Vietnam). "Cà phê" in Vietnamese was derived from the French café (coffee). Yogurt in Vietnamese is "sữa chua" (lit. "sour milk"), but also calqued from French (yaourt) into Vietnamese (da ua - /j/a ua). "Phô mai" (cheese) is also derived from the French fromage. Musical note was borrowed into Vietnamese as "nốt" or "nốt nhạc", from the French note de musique. The Vietnamese term for steering wheel is "vô lăng", a partial derivation from the French volant directionnel. The necktie (cravate in French) is rendered into Vietnamese as "cà vạt".

In addition, modern Vietnamese pronunciations of French names remain directly derived from the original French pronunciation ("Pa-ri" for Paris, "Mác-xây" for Marseille, "Boóc-đô" for Bordeaux, etc.), whereas pronunciations of other foreign names (Chinese excluded) are generally derived from English pronunciations.

Some English words were incorporated into Vietnamese as loan words, such as "TV" borrowed as "tivi", but still officially called truyền hình. Some other borrowings are calques, translated into Viet, for example, 'software' is translated into "phần mềm" (literally meaning "soft part"). Some scientific terms such as "biological cell" were derived from Chữ Hán, (細胞), whilst other scientific names such as "acetylcholine" are unaltered. Words like "peptide", may be seen as peptit.

Japanese loanwords are a more recently studied phenomenon, with a paper by Nguyen & Le (2020) classifying three layers of Japanese loanwords, where the third layer was used by Vietnamese who studied Japanese and the first two layers being the main layers of borrowings that were derived from Japanese.[50] The first layer consisted of Kanji words created by Japanese to represent Western concepts that were not readily available in Chinese or Japanese, where by the end of the 19th century they were imported to other Asian languages.[51] This first layer was called Sino-Vietnamese words of Japanese-origins. For example, the Vietnamese term for "association club", câu lạc bộ, which was borrowed from Chinese (俱乐部; pinyin: jùlèbù; jyutping: keoi1 lok6 bou6), which was borrowed from Japanese (kanji: 倶楽部; katakana: クラブ; rōmaji: kurabu) which came from English ("club"), resulting in indirect borrowing from Japanese.

The second layer was from brief Japanese occupation of Vietnam from 1940 until 1945. However, Japanese cultural influence in Vietnam started significantly from the 1980s. This new, second layer of Japan-origin loanwords is distinctive from Sino-Vietnamese words of Japanese-origin in that they were borrowed directly from Japanese. This vocabulary included words representative of Japanese culture, such as kimono, sumo, samurai, and bonsai from modified Hepburn romanisation. These loanwords are coined as "new Japanese loanwords". A significant number of new Japanese loanwords were also of Chinese origin. Sometimes, the same concept can be described using both Sino-Vietnamese words of Japanese origin (first layer) and new Japanese loanwords (second layer). For example, judo can be referred to as both judo and nhu đạo, the Vietnamese reading of 柔道.[50]

Some words such as lạp xưởng from 臘腸 (Chinese sausage) primarily keeps to the Cantonese pronunciation, brought over from southern Chinese migrants, whereas in Hán-Việt, which has been described as being close to Middle Chinese pronunciation, is it actually pronounced lạp trường. However, the Cantonese term is the more well known name for Chinese sausage in Vietnam. Meanwhile, any new terms calqued from Chinese would be from Mandarin into Sino-Vietnamese pronunciation. Additionally, in southern provinces of Vietnam, the name xí ngầu can be used to refer to die, which may have derived from a Cantonese or Teochew idiom "xập xí, xập ngầu" (十四, 十五, Sino-Vietnamese: thập tứ, thập ngũ) meaning "fourteen, fifteen" meaning 'uncertain'.

Other words, like muôn thuở meaning forever are seen to be purely Vietnamese invention, which used to be scribed Nôm characters, which were compounded Chinese characters, which are now written in romanized script.

From around the 13th century, Vietnamese scholars used their knowledge of the Chinese script to develop the chữ Nôm (lit. 'Southern characters') script to record folk literature in Vietnamese. The script used Chinese characters to represent both borrowed Sino-Vietnamese vocabulary and native words with similar pronunciation or meaning. In addition, thousands of new compound characters were created to write Vietnamese words using a variety of methods, including phono-semantic compounds.[62] For example, in the opening lines of the classic poem The Tale of Kieu,

• the Sino-Vietnamese word mệnh 'destiny' was written with its original character 命;
• the native Vietnamese word ta 'our' was written with the character 些 of the homophonous Sino-Vietnamese word ta 'little, few; rather, somewhat';
• the native Vietnamese word năm 'year' was written with a new character 𢆥 that is compounded from 南 nam and 年 'year'.

Nôm writing reached its zenith in the 18th century when many Vietnamese writers and poets composed their works in Nôm, most notably Nguyễn Du and Hồ Xuân Hương (dubbed "the Queen of Nôm poetry"). However, it was only used for official purposes during the brief Hồ and Tây Sơn dynasties (1400–1406 and 1778–1802 respectively).[63]

A Vietnamese Catholic, Nguyễn Trường Tộ, unsuccessfully petitioned the Court suggesting the adoption of a script for Vietnamese based on Chinese characters.[64][65]

A romanization of Vietnamese was codified in the 17th century by the Avignonese Jesuit missionary Alexandre de Rhodes (1591–1660), based on works of earlier Portuguese missionaries, particularly Francisco de Pina, Gaspar do Amaral and Antonio Barbosa.[66][67] Still, chữ Nôm was the dominant script in Vietnamese Catholic literature for more than 200 years.[68] Starting from the late 19th century, the Vietnamese alphabet (chữ Quốc ngữ or "national language script") was gradually expanded from its initial usage in Christian writing to become more popular among the general public.

The Vietnamese alphabet contains 29 letters, including one digraph (đ) and nine with diacritics, five of which are used to designate tone (i.e. à, á, ả, ã, and ạ) and the other four used for separate letters of the Vietnamese alphabet (ă, â/ê/ô, ơ, ư).[69]

This romanized script became predominant over the course of the early 20th century, when education became widespread and a simpler writing system was found to be more expedient for teaching and communication with the general population. The French colonial administration sought to eliminate Chinese writing, Confucianism, and other Chinese influences from Vietnam.[65] French superseded Chinese in administration. Vietnamese written with the alphabet became required for all public documents in 1910 by issue of a decree by the French Résident Supérieur of the protectorate of Tonkin. In turn, Vietnamese reformists and nationalists themselves encouraged and popularized the use of chữ Quốc ngữ. By the middle of the 20th century, most writing was done in chữ Quốc ngữ, which became the official script on independence.

Nevertheless, chữ Hán was still in use during the French colonial period and as late as World War II was still featured on banknotes,[70][71] but fell out of official and mainstream use shortly thereafter. The education reform by North Vietnam in 1950 eliminated the use of 'chữ Hán and chữ Nôm.[72] Today, only a few scholars and some extremely elderly people are able to read chữ Nôm or use it in Vietnamese calligraphy. Priests of the Gin minority in China (descendants of 16th-century migrants from Vietnam) use songbooks and scriptures written in chữ Nôm in their ceremonies.[73]

Chữ Quốc ngữ reflects a "Middle Vietnamese" dialect that combines vowels and final consonants most similar to northern dialects with initial consonants most similar to southern dialects. This Middle Vietnamese is presumably close to the Hanoi variety as spoken sometime after 1600 but before the present. (This is not unlike how English orthography is based on the Chancery Standard of Late Middle English, with many spellings retained even after the Great Vowel Shift.)

The Unicode character set contains all Vietnamese characters and the Vietnamese currency symbol. On systems that do not support Unicode, many 8-bit Vietnamese code pages are available such as Vietnamese Standard Code for Information Interchange (VSCII) or Windows-1258. Where ASCII must be used, Vietnamese letters are often typed using the VIQR convention, though this is largely unnecessary with the increasing ubiquity of Unicode. There are many software tools that help type Roman-script Vietnamese on English keyboards, such as WinVNKey and Unikey on Windows, or MacVNKey on Macintosh, with popular methods of encoding Vietnamese using Telex, VNI or VIQR input methods. Telex input method is often set as the default for many devices.

Vietnamese speak date in the format "day month year". Each month's name is just the ordinal of that month appended after the word tháng, which means "month". Traditional Vietnamese however assigns other names to some months; these names are mostly used in the lunar calendar and in poetry.

When written in the short form, "DD/MM/YYYY" is preferred.

Example:

• English: 28 March 2018
• Vietnamese long form: Ngày 28 tháng 3 năm 2018
• Vietnamese short form: 28/3/2018

The Vietnamese prefer writing numbers with a comma as the decimal separator in lieu of dots, and either spaces or dots to group the digits. An example is 1 629,15 (one thousand six hundred twenty-nine point fifteen). Because a comma is used as the decimal separator, a semicolon is used to separate two numbers instead.

Although regional variations developed over time, most of these words can be used interchangeably and be understood well, albeit, with more or less frequency then others or with slightly different but often discernible word choices and pronunciations. Some accents may mix, with words such dạ vâng, combining dạ and vâng, being created.

The syllable-initial ch and tr digraphs are pronounced distinctly in North-Central, Central, and Southern varieties, but are merged in Northern varieties (i.e. they are both pronounced the same way). Many North-Central varieties preserve three distinct pronunciations for d, gi, and r whereas the North has a three-way merger and the Central and South have a merger of d and gi while keeping r distinct. At the end of syllables, palatals ch and nh have merged with alveolars t and n, which, in turn, have also partially merged with velars c and ng in Central and Southern varieties.

In addition to the regional variation described above, there is a merger of l and n in certain rural varieties in the North:[76]

Variation between l and n can be found even in mainstream Vietnamese in certain words. For example, the numeral "five" appears as năm by itself and in compound numerals like năm mươi "fifty" but appears as lăm in mười lăm "fifteen" (see Vietnamese grammar#Cardinal). In some northern varieties, this numeral appears with an initial nh instead of l: hai mươi nhăm "twenty-five", instead of mainstream hai mươi lăm.[lower-alpha 13]

There is also a merger of r and g in certain rural varieties in the South:

The consonant clusters that were originally present in Middle Vietnamese (of the 17th century) have been lost in almost all modern Vietnamese varieties (but retained in other closely related Vietic languages). However, some speech communities have preserved some of these archaic clusters: "sky" is blời with a cluster in Hảo Nho (Yên Mô, Ninh Bình Province) but trời in Southern Vietnamese and giời in Hanoi Vietnamese (initial single consonants /ʈ/, /z/, respectively).

Although there are six tones in Vietnamese, some tones may slightly "merge", but are still highly distinguishable due to the context of the speech. The hỏi and ngã tones are distinct in North and some North-central varieties (although often with different pitch contours) but have somewhat merged in Central, Southern, and some North-Central varieties (also with different pitch contours). Some North-Central varieties (such as Hà Tĩnh Vietnamese) have a slight merger of the ngã and nặng tones while keeping the hỏi tone distinct. Still, other North-Central varieties have a three-way merger of hỏi, ngã, and nặng resulting in a four-tone system. In addition, there are several phonetic differences (mostly in pitch contour and phonation type) in the tones among dialects.

The table above shows the pitch contour of each tone using Chao tone number notation (where 1 represents the lowest pitch, and 5 the highest); glottalization (creaky, stiff, harsh) is indicated with the ⟨◌̰⟩ symbol; murmured voice with ⟨◌̤⟩; glottal stop with ⟨ʔ⟩; sub-dialectal variants are separated with commas. (See also the tone section below.)

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