There's one big problem I can see with the use of key words, and that is the difference between English & American spelling. Unless you are going to give alternative spellings for every key word (a right pain) the player may run into a problem caused by spelling difference.
There is also the problem a large number of people seem to have in spelling words like 'Rogue' correctly. I've even seen professional games with things called 'Rings Of The Rouge' in them...
And that's without considering alternate words that mean the same thing, or the use of local slang... You'd need to include huge numbers of synonyms if you are to avoid driving the players crazy.
It's a lovely idea, but very hard to implement without serious problems, IMO.
