Faster Press and Hold Character Picker Does anyone know how to make the character picker appear more quickly? 

I use it enough now in my German language studies that it has become second nature for the critical marks and much faster than using the alt+keypress shortcuts. 

Only problem is that it's so second nature that sometimes it doesn't pop up quickly enough so I end up typing the character and the number shortcut sometimes (IE u2 instead of ü). Anyone know how to make it appear with less delay? Ideally, I'd love if I could just hold the character and press the number but it appears that OSX insists on waiting for the menu to pop up.
The "Character Accent Menu" settings can be adjusted under: 

System preferences -> Keyboard -> Delay Until Repeat

If you reduce this time, it's the fastest way to insert any accents in my experience. Setting the initial key repeat rate is the same as setting the time for the character accent menu to appear. With this solution, there is no need to change to international keyboards etc (see the other answers). see here. 

If you set it to the minimum value, the delay will be 15 ms, which should be quite fast. However, there seems to be an actual delay of about 300 ms until the menu appears (maybe displaying the menu takes a while? Don't know). 



There's people using scripts to set the delay from 15 to 1 ms, but I'm not sure whether this helps: see here: github.com/mathiasbynens/dotfiles/blob/master/.macos, the relevant parameter is InitialKeyRepeat