Inserting special characters when using Windows is a pain in the ass. It's possible if you know the Unicode point (in decimal, no less) of the character and have a numpad, but otherwise there's no way to do it that works system wide. Even more perverse is the fact that this functionality is present in Microsoft Word (not all of Office, mind you), meaning Microsoft acknowledges this deficiency. Mac OS has system-wide shortcuts for pretty much any special characters. The Linux distributions I've used have allowed custom shortcuts for all characters.
I currently only write in two languages on a regular basis, but that number has been as high as five in recent years, and it probably will be again. I needed this functionality (system-wide, not just in Word), and I know a lot of other people who do (or did) as well.
So I made a thing. Yours for free*.
Install, then run. To insert a character, hold CTRL+ALT (you can chage this to some other key combination) and then the key(s) for the character you want to set (also configurable).
I apologize for the config editor. It's usable though, and you're welcome to edit the config file in a text editor (C:/Users/[your username]/shortcuts.kse).
*As in free beer and freeish speech. CC-BY-SA.