i'm using frei-chat with elgg. one of the developers upgraded to the new version but i'm still unable to chat in arabic, hebrew, chinese languages
what should I do to make visitors chat in their own language

Can you leave a screenshot here so as to understand what is happening.

when i type anything in arabic, i can see it coorectly on my computer but the person i'm chatting with can only see "??????"
so a screen shot will not help much

but if he replies in arabic, do you see the ???? symbols, if you don't see these then it has to be something related to the browser.

when he types in arabic i also see ????

Do you have the translate enabled / set to some other language
while chatting ?

i have not changed anything, so i assume it's not enabled. how do i enable it?

We would like to test the translation and chat in your website .

So , can you provide us with two login accounts and your website url .
You can send it using the contact us form .