Receiving E-mail in other Languages

I am currently running Win2k, I have it set up to write in Thai and Korean Fonts, the main Language of the OS is English.
I can write documents in all 3 languages.
I can read websites in all 3 languages.
I can send but not recieve emails in non-Roman fonts. They appear scrambled.
I can chat in Thai and Korean on MSN Messenger but if I try it on Yahoo Messenger the script does not appear at all. And I cannot see script in those languages on yahoo messenger.
My internet options, regional options and keyboard options all seem to be ok.
They are set up for English, Korean and Thai… What is the problem?