Accent popup in Terminal.app?

This can be done with a bit of hacking. ;)

Before proceeding, you should backup your Terminal’s preferences file:

cp "Library/Preferences/com.apple.Terminal.plist" "Library/Preferences/com.apple.Terminal_OLD.plist"

Check to see if the file was copied successfully:

ls "Library/Preferences/com.apple.Terminal_OLD.plist"

If it prints Library/Preferences/com.apple.Terminal_OLD.plist then you're good to go. Otherwise make sure you typed the first command correctly.

Now for the fun part, you can modify the internal settings of the Terminal by typing:

defaults write com.apple.Terminal "ApplePressAndHoldEnabled" -bool true

Close the Terminal completely by first closing all open Terminal windows and then right clicking the Dock icon and choosing Quit.

Open the Terminal again and smile :)

Let me know if this doesn't work on your system.