During the MIX 11, it was announced that Microsoft will be expanding Windows Phone 7.5 "Mango" language support to 16 different languages, including East Asian languages such as Chinese, Korean and Japanese.
Microsoft will also refreshing the Metro look as well, Zheng saying that "[The Windows Phone design team had already indicated they were hard at work on the evolution of Metro." Of course, with Microsoft applying the Metro design language on certain touch-based elements of Windows 8 and Office 15 as well, there's definitely elements that could be better tweaked to accommodate the wider range of devices and screen-sizes.
Long Zheng has shaed some more information about this upcoming. As illustrated on the keynote slide above:
East Asian support is not only the introduction of a new character set but actually a slightly modified implementation of the Metro design language.
To accommodate the bigger size of character-based writing, the Windows Phone design team is adopting a vertical text layout to reduce the amount of text clipping that would occur more frequently (than it already does). The vertical text will not be limited to just the date and time on the lock screen but will also be featured in hubs (panoramas) and other native apps.
Zheng also mentioned that the vertical layout mightn't come as part of the templates that comes with the official "Mango" SDK, indicating that third-party apps might need to emulate the effects in their apps.