As a kid, I enjoyed saying things into Windows Voice Recorder and then pressing the Reverse button.
I'd figure out what the backwards gibberish sounded like.
Then I'd try to speak the backwards message, and reverse THAT, and see how close I was to my original topic.
Trust me, it's not inconceivable that someone would sit there with headphones and a microphone and learn a couple backwards forwards words.
I did it out of boredom. Imagine if I had to get a message to a lot of people but have very little channels to do so (thanks to Q team and NSA patriots.) I'd also have plausible deniability when called on it, because I'd say, "what, go play some Zeppelin records backwards you tinfoil hatter, I'm not talking backwards!"
Just saying, one could learn and memorize even just a few short statements and pull them out when needed.
Not that I think he really was saying "I need a gag," but you get the idea.