Lurking inside your World of Warcraft folder is a folder called WTF. While this has often prompted me and, I'm sure, others to exclaim "WTF indeed," I have recently learned that it stands for Warcraft Text File, instead of a more colorful alternative. Oh well. Inside the WTF folder, you will find the humble Config.wtf, a plain text file that contains many saved settings from WoW. Specifically, it stores most of your interface preferences, like graphics, audio, camera, and such.
And if you wanted to, you could open the document up in WordPad/TextEdit (depending on OS; apparently NotePad is not good to open Config.wtf in), and change the preferences therein, and they would apply to your game. It's pretty simple. For instance, the line for the profanity filter reads
SET profanityFilter "0" in my Config.wtf, since I have it turned off. If you wanted to turn it on, you'd change the 0 to a 1, and it would read
SET profanityFilter "1"; save the file, and your profanity filter is now turned on next time you run WoW. Note that you may not have a line for all possible options if they're at default values.