I would have never believed this if I hadn't seen it with my own eyes. A friend has a golden retriever that I was playing with one day, and I asked him to get me a stick. He did, but it wasn't the stick I was thinking of, so I just off hand said, "no, not that stick, the one by the rock." and damn if that dog didn't drop it and go get the one by the rock. So I said, "put that stick with the other stick." Bam, done. I was stunned. I told my friend and he said, "oh, yeah, not surprised. He's smart." Now, maybe he didn't fully understand the sentences, and was simply understanding my body language and watching my eyes, movements, etc for clues, but even if so... dang.
Now, my dimwitted sweetheart of a pup often gets confused just between "sit" and "down", but I love her anyway :)