Can't change Joomla Default language

On this site http://www.bostonteaclub.com I want the default language to be Chinese. I set the default language to Chinese in the backend (it's got the star next to it) but when you w开发者_Python百科ent to the page you probably noticed that the site is displaying in english.

If you check the source code you will see on the very bottom hidden a var_dump of the language object, and by the looks of it the default is still en-GB

["_default"]=>
  string(5) "en-GB"

Why is this? Thanks

EDIT The default language is used when a language file in the requested language does not exist.

Still the problem remains, why does the site not default to chinese? you can change the language of the site and it works in Chinese http://www.bostonteaclub.com/中文版

EDIT 2 Even JoomFish say "Site default language: 中文版." In the administration...

Here we go:
I found when going to the plugins the 'System - Jfrouter' is the perpetrator!
I disabled Language determination and discovered the "Language selection for new visitors" to be very helpful to. Bonus: this is the plugin that lets you choose weather to use SEF Prefix or Sub-Domains for the language selection.
Hope this helps for any future people looking how to solve this problem.
peace =)

If I well remember Joomfish it's auto-sense about the default language. It use by default what it's specified in the user agent string.

Try this:

• Add Chinese as language and set it as default in the browser preferences.
• Reopen your browser, to clear the sessions cookies and surf back to your site, it should be in Chinese.