Disable ‘press and hold’ option in Mac OS X 10.7+

If you press and hold a letter in OS X, a pop-up will appear with the various accented versions of that letter. If you don’t use this and it bothers you, you can disable it.

defaults write -g ApplePressAndHoldEnabled -bool false

Restart your Mac or logout/in to make the changes appear

Revert back to default with:

defaults write -g ApplePressAndHoldEnabled -bool true

Screencast: