The Vietnamese alphabet (chữ Quốc ngữ in Vietnamese) is a version of the Latin alphabet used to write the Vietnamese language. It uses all of the letters of the ISO Basic Latin Alphabet except for F, J, W, and Z (which are only found in loanwords). However, the alphabet has been changed heavily in order to accurately show Vietnamese pronunciation. Some letters and digraphs make very different sounds than what most readers of the Latin alphabet expect, such as D, R, and GI. One letter has been added, Đ, to show it is a completely different sound from D. Vowel markers are added in order to distinguish different vowel sounds like A, Â, and Ǎ. Tone markers are also added, because Vietnamese is a tonal language, such as Á, Ả, Ã, Ạ, and À. Some vowels have both a vowel marker and a tone marker. For example, the vowel Ǎ can be written as Ắ, Ẳ, Ẵ, Ặ, and Ằ. Sometimes, even non-speakers of Vietnamese can tell something is written in Vietnamese simply based on how many markings a word can have.

History 
Unlike many other Asian languages that are mainly written using an Asian-made writing system, Vietnamese is mainly written using the Latin alphabet, which came from Europe. Before the Vietnamese used the Latin alphabet, they used a writing system based on the Chinese character system called chữ nôm. Chinese loanwords were written the same as they were in Chinese, but thousands more characters were invented write native Vietnamese words. Due to the amount of time it took to learn the system, the literacy rate in Vietnam was low when this system was used.

In the 17th century, Portuguese Catholic missionaries created a writing system based on their own Latin alphabet to translate Vietnamese and to make it easier to learn for Europeans. When Vietnam first became a French colony, the Vietnamese alphabet and 'chữ nôm' were used alongside each other. Today, however, only the Vietnamese alphabet is used in Vietnam, and very few Vietnamese can read 'chữ nôm.'

Letters of the alphabet

Vietnamese characters
Here is the total set of characters for the lowercase letters:

The little ₫ is just the Dong (Dollar) sign - most people just write VND for Vietnamese Dong - the currency of Vietnam.

This makes the useful alphabet 89+ letters.
I.e.
This letter is a word: 'ở, it means at (or where, place).

The Latin alphabet
The main letters from the Latin alphabet:

a, b, c, d, e, g, h, i, k, l, m, n, o, p, q, r, s, t, u, v, x, y, qu

The first set of changed letters
ô, ơ, â, ă, ê, ư, d

This changed set of characters makes new alphabet letters for use in the Vietnamese language. They are an extension to the set of Latin characters already used. English doesn't extend the alphabet. English just uses the same written characters over again, to denote different (letter) sounds. For example: ape, angry, all, art, aorta, and apple. For the Vietnamese language, sounds are split up with their own letter/character changes.

 'đ' is makes the same sound as the English d.
 'd' in the Vietnamese alphabet is y (in Southern Vietnam), 'd' is z (in Northern Vietnam).
 'a, â, ă' are just different ah letters.
 'u, ư' are different oo letters - never, ever an uh/ah sound.
 'e,  ê' are just eh and ey - but they may sound different to English e in use.
 'o, ô, ơ'  are just oh, oe, and ur - but they still all sound like o's from English.

Note: i and y are essentially the same vowel (and may be exchanged in some situations)

The school alphabet
The alphabet is taught in Vietnam's schools with these letters

a, b, c, d, e, g, h, i, k, l, m, n, o, p, q, r, s, t, u, v, x, y - ô, ơ, â,  ă, ê, ư, đ 

Vietnamese schools teach the alphabet with these 29 letters. The total number of possible letters is much higher if diacritical marks are added.

The F, J, W, Z are not used in native Vietnamese words. Only loanwords borrowed from other languages use these letters.

Making the vowel sounds
These are the tone rules for vowels with different sounds. It's like music where only the correct sound can come from the instrument. It doesn't matter which instrument, as long as the sound follows the rules.

	
Note: This is a spoken language so musical pitch or lilt is not the most changed sound quality. Different voices have different musical pitches. What the speaker will change is the intensity, and time given to the sound parts for each letter (or word). If a speaker uses strong pitch changes, it will probably be for pronunciation.

Treatment of the Alphabet

Sounds similar to letters
Before, the alphabet was arranged from 'a to z' by foreign dictionaries, it included two letter sounds. The letters are like two letter sounds in English. 'Ch' in mechanic, or Christmas are good examples. In Viet characters the 'j'(jeh) sound has an equal (sound) that is written as 'tr'(jeh). Letters like 'Tr' used to be in every dictionary's order right in between the other alphabet letters. Another sound is 'ph'. 'Ph' is very famous - it's used in 'phở' the most famous Vietnamese soup in the world. 'Ph' is an 'f' sound, just like in English - 'phone'. 
In addition to the normal alphabet consonants, there are nine possible double-letters and one triple-letter.

 CH
 GI
 GH
 KH
 NG
 NGH
 NH
 PH
 TH
 TR (preserved as "T + R" by some Southern (Vietnam) speakers).

The order

The syllables
Because of a relationship with East Asian languages (Japanese,Chinese etc.) the Vietnamese words can be moved around in their order. The reversal of the syllable-words moves them to another position in the dictionary. Also, the syllable-words can be held behind different syllable-words - like the articles in English. It's best to use a computer query to find them.

The alphabet in daily life
Young Vietnamese learners will spend a lot of time with this alphabet. Correction is very common. The need for correction is used in many comedies about uneducated people. Comedies about foreigners are becoming very common too. 
The reason for all the attention is how quickly the meaning will change. To say "I have a sore head, somewhere" ("đầu của tôi là đau đâu!" in Vietnamese) is nearly impossible for (foreign) learners on their first day. A learner will only hear 'dow, dow dow' or 'dough, dough, dough' or 'dow, dough, dough' which does not help when listening. The same problem can be stated in English - 'four forks for foreigners' foreheads forthwith!'  
Each word in Vietnamese can be identical to another word, except for the sounds/tones/letter-changes. The sound is also identical to the ears of English speakers that allow for expression (sound changes) still.   

See: Vietnam Eyes lesson on YouTube

Foreign characters/letters

From English
The world includes Vietnam! So, the other letters 'j, f, w and z' are now OK to use in many places - on billboards, posters, T-shirts...  But, if you work for any type of Vietnamese authority or association, then limit their use until the authority declares them as acceptable letters. But, the other alphabets that are used in English might not be accepted. For example: the Greek alphabet is very useful for English speakers - but in Vietnam it can lack meaning - it would be a decoration for the general population. Educated people will know more letters from the Greek alphabet.

From Chinese
Vietnamese used to be written in Chinese characters. A variety for Vietnamese is used in traditional culture. Many Chinese speakers find Vietnamese easy to grasp. The combination of two words is very common to Chinese. Example: phat am, Hong Kong/Xiong Gong etc. .

Combined characters
'Diphthongs' are the next most important step to understanding the use of Vietnamese letters. The combination of toned vowels as dipthongs and triphthongs makes the Vietnamese language very fast. Some phrases can be spoken clearly without a strong clarity from consonants. It's very hard for English speakers to follow the combinations of sounds, especially vowels.

Northern vs. southern accent 
There are many differences between northern and southern dialects of Vietnamese. Hanoi is the standard for northern dialects and Saigon is the standard for southern dialects.

Differences in pronunciation include

 As mentioned earlier, northern Vietnamese pronounce the letter D like the English "Z", while southern Vietnamese pronounce it like the English "Y". For example, Diem would sound like "ziem" in northern accents, but like "yem" in southern accents.
 Northern Vietnamese also pronounce the letters GI like the English "Z", while southern Vietnamese also pronounce it like the English "Y". For example, Giap would sound like "zap" in northern accents, but like "yap" in southern accents.
 Northern Vietnamese pronounce the letter R like the English "Z", while southern Vietnamese pronounce it like the English "R". For example, Rang would sound like "zang" in northern accents, but like "rang" in southern accents.
 Northern Vietnamese pronounce the letter V like the English "V", while southern Vietnamese pronounce it like the English "Y". For example, Viet would sound like "viet" in northern accents, but like "yet" in southern accents.
 Northern Vietnamese pronounce the letter S like the English "S", while southern Vietnamese pronounce it like the English "SH". For example, Saigon would sound like "saigon" in northern accents, but like "shaigon" in southern accents.

The alphabet in computers

The Vietnamese keyboard is always virtual (in software). Nobody can buy a computer keyboard for Vietnamese, in Vietnam. The common QWERTY keyboard is used in Vietnam. Software programs for Vietnamese characters are very common.

On a webpage
The webpage is usually set to include the UTF-8 standard when using the Vietnamese alphabet. If the design of the characters is strange the designer of a web-page will set the font to plain "Arial". Some special fonts have been made for Vietnamese alphabets.

Javascript codes
<script type="text/javascript">

document.write("\ta"+"\tb"+"\tc"+"\td"+"\te"+"\tg"+"\th"+"\ti"+"\tk"
+"\tl"+"\tm"+"\tn"+"\to"+"\tp"+"\tq"+"\tr"+"\ts"+"\tt"+"\tu"+"\tv"+"\tx"+"\ty"
+"\u00E0"+"\u00E1"+"\u00E2"+"\u00E3"+"\u00E8"+"\u00E9"+"\u00EA"+"\u00EC"
+"\u00ED"+"\u00F2"+"\u00F3"+"\u00F4"+"\u00F5"+"\u00F9"+"\u00FA"+"\u00FD"
+"\u0103"+"\u0111"+"\u0129"+"\u0169"+"\u01A1"+"\u01B0"+"\u1EA1"+"\u1EA3"
+"\u1EA5"+"\u1EA7"+"\u1EA9"+"\u1EAB"+"\u1EAD"+"\u1EAF"+"\u1EB1"+"\u1EB3"
+"\u1EB5"+"\u1EB7"+"\u1EB9"+"\u1EBB"+"\u1EBD"+"\u1EBF"+"\u1EC1"+"\u1EC3"
+"\u1EC5"+"\u1EC7"+"\u1EC9"+"\u1ECB"+"\u1ECD"+"\u1ECF"+"\u1ED1"+"\u1ED3"
+"\u1ED5"+"\u1ED7"+"\u1ED9"+"\u1EDB"+"\u1EDD"+"\u1EDF"+"\u1EE1"+"\u1EE3"
+"\u1EE5"+"\u1EE7"+"\u1EE9"+"\u1EEB"+"\u1EED"+"\u1EEF"+"\u1EF1"+"\u1EF3"+
"\u1EF5"+"\u1EF7"+"\u1EF9");

</script>

Open source
Some software is free to use. An open-source software program for the Vietnamese keyboard has already been written.

Downloaded keyboards
There are a few virtual keyboard systems to use.

References

Vietnam
Alphabets
Austro-Asiatic languages