Windows Phone 7 doesn’t currently offer support for non-Latin scripts. If you speak Greek, Russian, Japanese, Hindi, Chinese, Korean, Khmer, or any other language that uses a different set of symbols, you’re decidedly out of luck for official support, at least until late next year.
However, there is some respite in sight. It appears that Microsoft will allow text entry apps that can input these non-Latin symbols, like for the platform’s Thai release. A Japanese developer is currently working on a similar text entry app for hiragana, katakana and kanji, which could even make its way to the Marketplace. It’s still in beta, but downloadable as a .xap from his blog.
It might not be perfect or system wide, but at least it’s something.