You probably won't see the help center translated into other languages until Stack Exchange hires employees who are actually native in those languages (or a user native in the language translates it and hosts the translation somewhere).

Having said that, I want to clarify that there is a big difference between a site *about the Arabic language* and a site *in Arabic*. The Area 51 proposal is *about* the Arabic language, meaning that in general questions and answers will still be narrated in English, talking about the Arabic language. This is exactly how the [Spanish SE](https://spanish.stackexchange.com/) runs - very few questions are written entirely in Spanish. The same can be said about the [German SE](https://german.stackexchange.com/), which does have a slightly higher percentage of solely-German questions (but still not a majority) and, unlike the Spanish SE, actually uses English for all its tags.

The [Stack Overflow in Portuguese](https://pt.stackoverflow.com/) site is the first of its kind. It is a full alternative to Stack Overflow *entirely in Portuguese*. Meaning that English is nowhere to be found on that site (except maybe in code for that particular site). Since the only spoken language there is Portuguese, they kind of *require* a help center entirely in Portuguese, and Stack Exchange [hired an employee](https://blog.stackoverflow.com/2013/08/introducing-gabe-the-smiling-community-manager/) specifically for handling this community. They couldn't have done it all without him. They're also [currently hiring](https://stackexchange.com/about/hiring) Community Managers who are fluent in Spanish and Japanese, likely for similar purposes.

**Note:** I'm only pointing these things out to give you a better understanding of what an "Arabic Language" SE site would actually be. While I agree having the help center translated into other languages related to a particular site, there will likely be a lot more English on that site than you're expecting. It certainly won't be entirely in Arabic.