For Ubuntu 12.04 LTS, most computers cannot type some Khmer vowels such as ោះ ាំ ុំ ុះ etc. Don’t worry just follow this instruction, you’ll get it.
Open file “enviroment”, /etc/enviroment
Add this line : GTK_IM_MODULE=”xim”
Save and Restart Ubuntu
How to do:
Type these commands in terminal:
Enjoy your work!