Apple has released more info on new features in OS X 10.7 Lion. Of interest related to languages are:
+Voices in 23 languages (compared to 1 in Snow Leopard).
+Safari support for vertical text and Web Open Font Format (WOFF)
+New System Localizations in Arabic, Czech, Turkish, and Hungarian
+iOS-like access to accented characters via a pop-up dialogue when you click on a character
+General support for vertical text in apps other than Safari
+Fonts added for Bengali, Kannada, Malayalam, Oriya, Sinhala, Telugu, Ethiopic, Lao, Khmer, and Myanmar, plus color Emoji
+Improved Chinese, Japanese, and Vietnamese input methods