Arabic support for text layers (and other text-shaping languages)

Hi. Is there anyone here that understand these languages (I don’t) to help me provide proper support?
I made a change on Text Layer code and I want to fix any errors I could understand by your information…

Windows users are able to test it by following these steps: How to test changes in Pull Requests — Synfig User Manual 1.4.0 documentation

Please tag users that speak those languages.