I don't think it should be limited by the gov't. that would set a very scary precedent as well. You could have the gov't intially outlaw certain words..then more..and more..eventually you'll get down to realspeak and goodspeak...
more and more..and bammo, you have a 10,000 word dictionary that you are allowed to use...then 1000 words...then 10...then 4.."I love big brother"
not quite that bad, but i don't see how it would be enforceable and the moment it would be put on the books, there would be such an outrage.
with that said, i still believe you should personally be held responsible for your speech.
If you think about it, there are limits to the freedom of speech "cult" that most agree on. You can't scream "FIRE" in a crowded theater/space, you can't commit perjury, you can't really lie to authority figures and get caught..etc.
But hate speech is still there, still allowed and if you put it out for others to hear, you're pretty much on your own with the consequences.