1. There are several languages which (sometimes) use the Arabic script, but are not Arabic, like Kurdish, Turkish up until a century ago, Javanese etc.
2. Farsi sort-uses the Arabic script, with some glyphs unique to it
... so things can be more complex than just deciding "Is it Arabic?" . But I like the website!
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Right-to-Left languages with non-Arabic script are also often similarly mis-rendered. I'd given the more popular scripts as an example, like N'Ko and Adlam, but almost nobody in the West bothers to print those, plus I'm not familiar enough with them; so - Hebrew:
In the disconnected-form script, here's Hello:
שלום עולם
(sounds like: shalom)
do you see the squarish glyph at the end of each of these words? That's the final-form Mem consonant. But in the beginning or the middle of the word, its glyph is מ. So if you see:
םולש
that means someone printed it in left-to-right order of glyphs instead of right-to-left.
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These issues come up a lot in our LibreOffice RTL languages user group on Telegram:
https://t.me/+GY3UwBnlDN9mY2M8
and if you're particularly interested in Arabic, there's the Arabic-issues-specific group: