joomla 3.1.5 arabic language doesn't appear

Hi all,
I installed arabic language in joomla 3.1.5,
I configure as joomla docs and the arabic language is viewed in the language manager as a content language
I have three menus , all languages and arabic and engilsh, but the language switcher display just the english language

please any suggests...

the website ip: 174.122.148.163/~elias/joomla

thanks

Hi Elias,
It seems the problem with multiple language of your Joomla site, not come from OS Property.
We have just check a bit in your site, the default language is English, it works ok. But when i click ont Arabic flag. It shows Joomla site with default Joomla template (not the template of English language) and the Arabic language (correctly)
You can watch this video clip abt the languages in Joomla

Thanks
Dam