train him in your language. Be consistent and you can use blue for sit, anything, as long as you use the same word.
Bernie waits at the door. Sounds like previous owner has taught the dog manners and pack leadership. Your dog IS waiting for permission to exit the door. I use "ok" to release my dog. Wait means, stay still. Yes means you are doing great, keep doing it.
A cork given to him means you are the best dog in the world, fantastic! I save it for the jackpots these days.