Writing in Vietnamese

Part of my mission to learn Vietnamese is to learn how to write it. It is actually quite easy to learn since the spelling is tightly correlated to how the words are pronunced.
The Vietnamese alphabet is very similar to the latin, just containing 29 letters:
a, ă, â, b, c, d, đ, e, ê, g, h, i, k, l, m, n, o, ô, ơ, p, q, r, s, t, u, ư, v, x, y
As you can see, there are 6 letters not present in English alphabet, ă, â, đ, ê, ô, ơ and ư. There are also no f, j, w or z (but they are still present on Vietnamese keyboards). Beyond the extra letters there also five accents, called diacritics, which are used to decide how the word is pronunced. This is an extremely important part of the Vietnamese language, one word can have completely different meaning depending on how you pronounce it.
This is also what I currently find the most difficult about learning Vietnamese. I can tell the difference when I hear ma (ghost), má (mother) and mã (horse) is near impossible.
You can divide the new letters into three groups to make it easier to remember:
Hat: â, ê, ô
Horn: ă, ơ, ư
Dash: đ
There are a couple of options when writing Vietnamese and a latin keyboard. The two most common layouts are Telex and VNI. There is also a layout called VIQR (Vietnamese Quoted-Readable) that uses 7-bit ASCII encoding and is therefore less common nowadays.
Telex and VNI (pronounced vini) are both common and from most Vietnamese knows how to use both of these from my understanding. Telex uses the base letter plus one or two more letters to form the final letter. VNI works similar but uses digits instead of letters.
For example nước (water) is written as nuwowsc in Telex. The logic is that w puts a "hook" on the letters a, o and u making uw into ư and ow into ơ. The s indicates that the letter preceding it should have an "up" tone. It is also common to write the tone of the word at the end, in the example nuwowcs. Telex has the advantage that you can write all letters just using the alphabet, for example when writing on a smartphone keyboard. I would also argue that Telex is faster to type when getting used to it.
In VNI, the way to write nước is instead no7u71c. Similar to Telex but with digits instead of letters. Another difference is that you have to put the tone right after the letter, not at the end of the word. VNI is especially useful when you mix between writing Vietnamese and other languages as you will not have unexpected tones and hooks appearing. With Telex, you need to escape out or change keyboard layout if you for example want to write the word "now" (which would become nư).
Here is how to write all Vietnamese special characters with the different layouts:
Letter
Telex
VNI
Example
â
a + a
a + 6
cây
ê
e + e
o + 6
tên
ô
o + o
o + 6
ngôi
ư
u + w
u + 7
lư
ơ
o + w
o + 7
nơi
ă
a + w
a + 1
ăn
đ
d + d
d + 9
đi
And for the tones:
Diacritic
Pronunciation
Telex
VNI
Example
á (acute)
up
a + s
a + 1
có
à (grave)
down
a + f
a + 2
và
ả (hook)
question
a + r
a + 3
nhỏ
ã (tile)
waving
a + w
a + 4
lũ
ạ (dot)
hard
a + j
a + 5
bạn
Both Telex and VNI can combine a diacritic and a tone by first writing the diacritic and then the tone. A good place to practice your Vietnamese writing skills is 10fastfingers.com.