You could simply have a string containing all your words with the default delimiter.
Then if you used the gettoken expression like so
would return "bat" in case of this example. Get it?
You could insert a random word easily into sentence for example:
"He opened the trunk and there it was: a giant "&Gettoken(string,Random(Numtokens(string)+1))
The Numtokens expression counts the number of tokens, the plus one is there because the Random expression is 0-based.
Hope that helped!