answered about 14 months ago by grubby
Unless you want to use the character map you'll need vietnamese keyboard input software. The two common packages are Vietkey and Unikey. The latter is free software and is available for download from http://www.unikey.org (Windows and Linux, although there are better alternatives for Linux - SCIM being the preferred method).
Once you have one of these programs installed you can switch to vietnamese mode and then type vietnamese diacritics following this guide:
http://www.unikey.org/manual/ukmanual.htm#telex
It's in vietnamese, but play around with it a little and you'll soon get it.
answered about 14 months ago by lcobb02
Just as an FYI, if you use Unikey, you type the vowel you want and then another letter which will add either a vowel mark or tone. Here are some of the most important functions.
Dot under a letter = j
cap on top of vowel = double vowel
đ = double d
ơ = ow
ỏ = or
õ = ox
down tone mark = f
up tone mark = s
good luck!