> If someone from Brazil writes a message using the letter é to multiple people, they would read as ة in Arabic, и in Russian and as a corner pipe (╔) if they’re using IBM’s code page 850.

Apologies for the minor nitpick: и is in Cyrillic, not Russian. Cyrillic is the script, Russian is the language. There are other languages that use Cyrillic besides Russian (and the script itself was developed around Greece/Bulgaria before Russia even existed).

For Arabic it's the language and the script so you're OK there!