Figured some ways to make TAB auto complete work for people who want to communicate with users who use characters outside of English language.
First mouse oriented system.
Clicking a name in the chat brings up the player menu with challenge, chat, profile, block and image.
If clicking the image is not going to be merged with profile. Then I suggest that clicking the image would automatically copy that name into the chat input. Alternatively it could just copy the name to clipboard but then people would lose their clipboard and most likely people would paste wrong names all the time.
Second is keyboard driven system.
Using TAB when a line starts with a special character(pick a key my example is “,”) would switch/rotate between the names that contain non English characters.
So typing “,” + TAB would replace the just typed “,” with the first non ANSI(or whatever) username in the chat channel. Hitting TAB again would switch to next user and so on. It could use user list or just people who have recently messaged in the chat.