There are problems with Arabic language.
1- If you are using English interface then you can't read Arabic language from the chat because the alignment goes wrong. It become from left to right instead from right to left and the letters are not connected.

2- the only solution is to use Arabic interface to read Arabic chat but there is crash bug. If someone write emojis on the chat then the crash will happen to all players who are using Arabic interface 'see the attachment'. Some players are using that bug to crash other players!!

Please fix these two problems.
I am now using English interface and the only way to read Arabic correctly and without having crash bug is by installing this mod:
https://mods.curse.com/mc-mods/minecraft/243639-truetype-font-replacement

but that is a temporary fix for my use and all Arabic players are suffering from wrong alignment in English interface and crash bug in Arabic interface.
Note: All bugs are effecting all minecraft version.