I spend too much time moving from my keyboard to my mouse.
I need a shortcut command list so I never have to remove my hands from the keyboard. Also, when I am in a lesson and I tab forward from a check box to what I think is a command button then I press enter I get re-directed from the lesson I was working on to the beginning of the lesson. inb4 just don't tab forward and nobody cares.
Most of the shortcuts are easy, but I agree with you that there needs to be a shortcut for the special characters. I knew about the german umlaut trick, but what about a ç for french? I don't know how many times in the first lesson I had to type garçon, and every time I had to click on the ç. Alt+0231 isn't very much faster, especially on my laptop.
If you go to the main vocabulary section on the top and click the vocabulary practice, you will see the duo owl always gives you a little speed tip... so some of these are for example: control + space bar to repeat the voice, up and down arrows for the drop down lists, type the first letter of your choice for the el or la box, type the number you want for the list of choices, Enter to move to the next question... Anyway those are off the top of my head. My advice is go to the Vocab and check out the owl for yourself :)