Is there any difference between window.listen(), screen.listen(), and turtle.listen()? 
I see them used differently in various programs but assume they can be called interchangeably.
turtle and screen have separate inputs.
For example:
turtle.onclick() and screen.onclick() may seem the same but screen.onclick() is referring to the general window while turtle.onclick() is referring to the turtle module itself.
Turtle
When calling turtle.onclick() you are activating the (onclick) function, to call your argument function whenever the user clicks specifically on the turtle object.
Screen
When calling screen.onclick() you are activating the (onclick) function, to call your argument function whenever the user clicks anywhere on the window.
This is equivalent to turtle.onscreenclick() because onscreenclick() refers to the entire screen. Hence the name screenclick rather than just click which refers to the turtle object.
Listen
So because turtle and screen have separate input functions, you'll need separate listening functions.
So
turtle.listen() listens for overall the entire turtle module's inputs, whilst screen.listen() listens for screen / window inputs.
Difference between turtle.listen() and screen.listen()