I usually write in English, but I often quote things in other languages like German or French. I know that you can set the language, like the font under Tools -> Language. Is there a keyboard shortcut to make this easier?
Go to System Preferences > Keyboard > Shortcuts and there will be various shortuc setups for almost anything. If you see something that is not listed, Make a service in Automator and add it as shortcut:
Here you see the service in Automator. It ain't always have to be an AppleScript. You can chose other services from the Menu on the left.
And here is a screenshot of enabling the service and assigning a shortcut by double clicking the shortucts on right, and pressing a combination of keys.
here is a full tutorial on services and automation as a little bonus to the question.