Did you additional install the MENA Arabic version of InDesign? You will need it. You can install it upon the existing version. No need to uninstall other versions.
Thank you for your answer Willi. Is there any possible way I could do this without Installing MENA on top of the version I currently run? I have all my settings, keyboard shortcuts etc on this version and I wouldnt want to loose these for one project.
Thank you again
You can do without MENA if you get a subscription to InDesign CC 2015. Then you could install the Arabic English on top of your US English or UK English version.
MENA versions are part of the CC subscription. Preferences are always limited to the language. If you look in the preferences, you will see different on each language, like English, English-Hebrew, English-Arabic, German, etc.
It is possible to move manually from one preset to another one, but be aware, that every language version has slightly different commands and therefore it could happen that the presets are not fitting in the other language.