My custom module does not show persian or arabic texts! I am developing a custom module. When I try to use Persian or Arabic text it does not show the text properly! The texts are shown in black square.
should I add anything?



As you see I installed Farsi language and menus are in Farsi but my custom text in module is not shown!
You have to install Locale module. Then you have to configure Arabic language. 


To get our languages hooked in, let's enable the core module, Locale.
Go to Languages section in admin -  admin/config/regional/language:
Click Add Language button

Then select Arabic form the drop down and save.



That's all you have to do :)