This is pretty easy to do in html since you could manipulate the elements easily.
I’m thinking the easiest way would be to create a xml file containing both mandarin and english version of the text for the menus and other elements. But what about the text dynamically created?
Is there an way to get all the texts during runtime and convert them into mandarin?
Seems like what you need is Silverlight Localization.. there are lots of solutions available about localization.. try this
http://www.wintellect.com/CS/blogs/jprosise/archive/2010/06/21/dynamic-localization-in-silverlight.aspx
for asian languages please have a look at it in order to display chiness/Japaneses langauges
http://msdn.microsoft.com/en-us/library/cc838238%28v=vs.95%29.aspx#displaying_chinese_japanese_and_korean_text