englishviacomputer

I think Apple should explain carefully on their web site how to be careful and not link up to iCloud and iTunes when you start up your mac.  They should warn that it is absolutely necessary to buy an external hard drive to make a copy of you system and software, because there is no built-in "Restore" like on a PC.  You put your restore on an external disk with the "Time Machine" application.

You even need this time machine if you want to get back your iPhoto, iMovie, and Garage Band if you have downloaded it to, say your Arabic or English system.  If you want to get those apps which come for free with your computer after you have restored to another system, say French.  You have to briefly attach the Arabic, say, Time machine disk, click on the actual icon of the hard disk and find the application you want and drag it over to the applications folder in your new (newly restored to a different language) computer.

You will end up having an assortment of Time Machine external disks for each system language you have.

I don't know if you can have all your different systems on one Time Machine external disk, but I doubt it.  I like to refer back to the Arabic, then the English, then the French systems.