Does a project manager require to speak in arabic? english speaker is it enough?

of course enlgish

Neither Arabic nor English is compulsory language in project management. Language basically depends upon the language of your team and associated stakeholders. 

It's a plus if the Project Manager knows how to speak Arabic since mostly,  are dealing with Arabic people. BUT english is a must for a PM since this is a universal language, and non-arabic employee will also be communicated through this medium of instruction.

أصبحت اللغه الانجليزيه مهمه ويمكن ان تكون شرط اساسى للقبول فى معظم الاعمال 

ولكن بالنسبه لمدير المشروع فانا أجده مهما ان يتحدث الانجليزيه نظرا لكثره التعامل مع الشركات متعدده الجنسيات 

Bilingual is indeed a value addition.

i believe that the language is not only be what you speak but how you communicate and understand other culture , in my experience i saw people didnt know each other language but they did great team work

I think English is a universal language and almost everyone understand this language to some extent. However, if the subardinates or the team member in your case are arabs and they don't speak engish then it is a must that the project manager must speak their language so that the objectives of the project are clear to them which will result on the successful completion of the project. This question lies in the communication aspect of the project management which is very important pillar for the projects.

I believe a project manager needs to be able to communicate with others, what is the value of a veteran in a certain aspect who is not able to share knowledge, as he is unable to communicate with others (most importantly listen to what others have to speak). Language will become a barrier, especially if the majority do not speak english. Culture is another barrier, which is needed to be considered in communications.

ليس من باب العنصرية ولكن بعض الدول ترفض التحدث الا بالغتها فلما لانكون مثلهم 

استخدم اللغه التي ستمكنك من التواصل مع العاملين في المشروع بطريقه جيده

It depends on the type of project and  the type of the stakeholders. But the most important part is team members , the clearer the mean of communication the better. For English speaker the team members ( at least the leaders ) should have enough level of understanding. Language barrier can be a major communication issue inside the project team.