Languages of Southeast Asia present a set of unique problems. Most require complex script support and have their own writing systems. Most don't use spaces between words, or use spaces between every syllable instead. Specifically: Burmese (Myanmar), Khmer (Cambodian), Lao, Thai, and Vietnamese.
Web Font Resources
Google has a little known resource called Early Access fonts which is accessible from the "More scripts" hyperlink on the upper right side of the page on the typical Google Fonts webpage.
As of 09/2014 numerous web-fonts are available in the Early Access resource offering support for the following languages:
Hebrew Lao Ethiopic Tamil Thai Korean
Arabic Bengali Hindi Myanmar Armenian Cherokee
Georgian Gujarati Gurmukhi Japanese Kannada Khmer
Malayalam Osmanya Telugu Chinese (traditional)
Using a Khmer Google Web Font
<link rel=stylesheet href="http://fonts.googleapis.com/css?family=Suwannaphum">
<p style="font-family: Suwannaphum,DaunPenh,Code2000;font-size:130%;">ខ្ញុំអាចញ៉ាំកញ្ចក់បាន ដោយគ្មានបញ្ហា</p>