CMS suggestion with multi language, and multi admin support

I'm planning on building a website that need to have certain feature, and it need to be done fast, so I decided to look for a ready built CMS. The problem is, I dont have many experience with CMS because I usually built everything ground up, so i heavily need your suggestion. Here is the requirement of the website:

1. support for multi language content. I need the website to have 2 languages which is English and Indonesia.
2. multiple admin access. There will be different category and pages on the sites, and I need a certain admin to be able to change or post only to their respective access or category or pages, granted by the superadmin
3. heavily customizeable html (honestly I dont know if this point is relevant or not)
4. PHP is an absolute. (CodeIgniter based framework is a plus, not a must)
5. MySQL. other DB is also okay.

on top of that, I an MVC based CMS would be very helpful.

Any suggestion would be very much appreciated. Thank you!!