Have to take your word for that. Never been lost for words and then suddenly a tiger comes into view and I think of something witty to say, but there is always a first time.

Its very easy. I would normally say "wow, look there is a tiger". You can say this as loud as possible. btw, if you notice kids they would do the same thing.

If you have to think of something witty or else you will get fed to the tiger, then I can see it having some effect.