Once they get going, there's no stopping them!
What IS spooky is that they can start forming grammatically-correct, cognitive sentences that suit the particular situation. Our CAG does this every, single day. When the place needs vacuuming, he says "This place is a mess!". Once the vacuuming is done, he says "Well, THAT looks better!". One day he wanted a cookie, and kept pestering my wife. She told him she was busy on the computer, and would get to him soon. His response? "Mommy - email me a cookie!". Now, I can tell you for a fact that he never, ever heard that sentence previously - he made it up to fit the circumstances. Recently, he started saying "I want a cookie, you old buzzard!" LOL. My wife wasn't impressed, so he didn't get a cookie when he added that epithet. Now, he asks sweetly for a cookie "Please Mommy, I'd like a cookie"...but he can often be heard muttering "...you old buzzard" under his breath afterward. He clearly considers it funny, and can't resist poking fun.
The first time you hear something like that from your Grey, you'll be tempted to chalk it up to coincidence. Maybe the second, third and fourth time, too. By the time you've experienced it hundreds of times, you will believe. These birds are incredibly intelligent, can understand abstract thought, and can put into words their wishes and observations.
It's spooky, and thrilling, simultaneously.