Our dog still prefers sign language to the spoken word. When we don't teach him new signs fast enough he invents his own, and then we are stupid idiots until we figure them out. Our favorites over the last year (all of which are things we didn't really want our dog to be familiar with in the first place) are:
HAND OVER YOUR SMART PHONE/iPAD
Oh, and my dog is still obsessed with Katy Perry's Roar. Even Olive is like, "OMG I am so sick of that song!"
And if you put on his Star Wars shirt he will start singing the Imperial March. Always.