I accidentally taught my dog the wrong name. He is my sweet baby, so I call him baby. He responds more to that than his name. It's funny because he knows his name but ignores it until we say "Hey Baby," so we joke that his name is Hey Baby.
When my kids were little, they got really into learning about fire prevention. As they learned to "Stop, Drop, and Roll," the dog did, too. It was the funniest thing because all you had to say was "Stop," and he would drop and roll. We did not try to train him to do this; he just copied the kids and picked it up.
I have a tendency to say "beep beep" when I'm trying to get around someone. For example, say I'm working in the kitchen and need to grab a spice, I'll say "beep beep" so my partner knows move out of the way. Well, now it works for my dog too. When I say "beep beep" my dog automatically starts backing up.