Ok. Here’s a few steps to get you started on translating the editor into a language we don’t currently support.
If you go to your editor settings you can change your language to be Arabic specific. You’ll find it under the Appearance section in your build, I believe.
Next you need to go to UE4\Engine\Config\Localization and open up the Editor.ini and Engine.ini. In there you’ll find a CulturesToGenerate array, you should add Arabic to both of these.You should consider removing the other language so as to not corrupt your content and iterate faster.
Next you should run the editor with the following cmdline:
-run=GatherText -config="…/…/…/Engine/Config/Localization/Engine.ini"
and then
-run=GatherText -config="…/…/…/Engine/Config/Localization/Editor.ini"
This will create the Arabic archive files. You’ll find them under UE4\Engine\Content\Localization. You can then enter translations into your archive files and re-run the above cmdlines. They will create/update your locres.
Your editor will automatically load the Arabic locres if your editor language is set to Arabic.
Be aware that there is a bug in the Language/Region settings that makes the setting only apply to the currently open project. So the splash screen won’t appear in Arabic since that appears before the project is loaded. You can get around this by changing your OS language/region to Arabic.
This should get you well on your way.
Unfortunately, we don’t have much support for your current goal. Good luck! Let me know how it goes!