Using a registry editor, go to the following key
HKEY_LOCAL_MACHINE\Software\Microsoft\FontLink\SystemLink

Change the font under the [HelveticaNeue LT 55 Roman],[HelveticaNeue LT 35 Thin] two strings into the Chinese font you already used.

Make it simple, normally you should find a string named "Tahoma" in the same area, and the value inside is exactly the Chinese font that you use now.

Now save the changes, and soft reset the phone :)