Unicode is standard allowing computers to consistently represent and manipulate text expressed in most of the world's writing systems.
Unicode consists of a repertoire of about 100,000 characters, Unicode encoding allow webmaster to use characters from different language on the same page. So it is possible to keep Chinese and Arabic characters at same page.
Most likely your browser use different characters encoding while viewing the page. So you need to make some ajustments to see page properly. Most users from North America by default use the Western ISO-8859-1 but users from different countries most likely will have different encoding.
If you see the weird characters on the page instead of the foreign text. That mean that encoding of your browser and encoding of webpage that you currently viewing is dirrerent. To view the page properly you must manually change the encoding of your browser. It is very easy: