Language Enabler activate all supported Samsung languages and keyboard inputs.
Starting with Android 4.2, the permission to change your system language became protected.
If you are familiar with Android developments tools, then you can grant the required permission to the App "pm com.wanam android.permission.CHANGE_CONFIGURATION"
If you have Root access on your device then Language Enabler can automatically do it for you.
This application supports all languages / locales: Arabic, Chinese, Indian, Spanish, French, Hebrew, Farsi... عربية، عبرية، فارسية.
There are some devices variants (US,Chinese) that remove completely all unused languages, sadly there is no much thing we can do in this case.
Please contact us if you need any help.