As anyone who uses a Mac knows, entering special characters is really easy–you just hold down a letter. That’s great if you want to play Pokémon Go with your friends mañana, but not so much if you realllllllllllllllllly want to play now.
Normally, on macOS, when you hold down a key, it will display a popup allowing you pick a special character if there are any assigned to that particular key.
If a key doesn’t have any special characters behind it and you hold it down, nothing will happen.
You can repeat some keys like space, backspace, and arrows, but that’s about it. So, how do you fix this?
You can switch it back to the more old school behavior–where holding a key repeats it–but it’s somewhat inconvenient. You can’t really have both options, since the hoop you have to jump through kind of makes it a this-way-or-that-way type of deal.
You have to use a command in the Terminal, which might seem easy enough except that in order to make it stick, you have to restart the computer. Want to change it back? Enter the command and restart again.
To do this, first open the Terminal from the Utilities > Applications folder.
With the Terminal open, now enter the following command and hit Return.
defaults write -g ApplePressAndHoldEnabled -bool false 
Next, restart your computer and you should now be able to repeat all characters.
Before you continue though, you might want to make sure that you adjust the repeat speed to suit your preferences. To do this, first open the System Preferences and then click open “Keyboard”.
The controls that apply are Key Repeat and Delay Until Repeat.
The first option will let you dictate how fast a key repeats. Note, if it is off, then keys won’t repeat at all.
The Delay Until Repeat option lets you decide how long it takes when you press and hold a key before it begins repeating.
If you want to reenable special characters, then you will need to enter the command in the Terminal again, change the last part to “true” and then again restart your computer.
defaults write -g ApplePressAndHoldEnabled -bool true Granted, this isn’t the most convenient way to go about switching between repeating and special characters. While you might not use one or the other often enough that this necessarily seems like a big problem, there are enough Mac users out there asking this very same question.
It would be far more convenient if Apple would simply add a checkbox to the keyboard preferences panel that lets you enable or disable special characters as needed.
Unfortunately, judging by a cursory Google search, this is a problem people have been looking into since at least OS X Lion, so its apparently something Apple doesn’t think needs fixing.