How did you make the application with English language? Did you hard code all the control texts?
I suggest you create 2 XML files, 1 for the English language and another 1 for the Arabic language that would look something like this:
<captions>
<form1 controlid="btnCancel" text="Cancel" />
<form1 controlid="btnOK" text="OK" />
</captions>
This will need you to make another class to read the XML file and use it to load the controls' texts though.
Hope this helps. :)