I looked at the code. It does not seem to use language files, like the rest of Q2A. So if you want to change it to your own language, you can simply look at all the files, specially https://github.com/svivian/q2a-chat-room/blob/master/qa-chat.php and change the text to your own.
For example, change this:
echo "QA_AJAX_RESPONSE\n0\nYou are not allowed to post currently, sorry.";
I don't know if there are plans to make this multlingual. If there is enough demand, I am sure Scott or someone else would.