Why Germans use the QWERTZ keyboard instead of QWERTY

Americans commonly use the QWERTY keyboard, thus named for the first six letter keys in the top left of the keyboard, but ...
Ars Technica

How do you type accented letters on-the-fly? (and other keyboard shortcuts!)

I don't know if this is really tech-ey enough to go in the software forum... How do you type accented letters on-the-fly with a standard US keyboard? How about letters like "ñ"? Is there some key ...