“Games give you a chance to excel, and if you're playing in good company you don't even mind if you lose because you had the enjoyment of the company during the course of the game.” ― Gary Gygax
(Just got the game, haven't played.)
Are you allowed to write things down during the whispering phase? I would assume not, because the descriptions I heard before buying the game all included "it can be hard to remember all the clues, that's part of the challenge" -- but I didn't see anything in the rules about it.
No, you may not.
There are 4 rounds of whispers: the squares of the Whisper tile indicate on each round which players whisper their clues to the player next to them. Try to remember the clues you receive as best you can to pass them on efficiently to the other players! When you whisper, you must pass on your clues as well as all those you’ve received so far from the other players.
Be careful: whisper so that the other two players don’t hear you!
When you receive clues, you cannot ask questions of the player whispering them to you (you can only ask them to repeat).
Be careful: when you receive clues, you do not give out your own clues in return.
Once the 4 rounds of whispering are done, secretly note what you remember.
Having the Notes made in a separate phase is what makes the game challenging.