My German shepherd doesn’t obey my wife. What can we do?

I really enjoy your web page. I believe I've read most of your training articles but don't know how to get my 6 1/2 month old male GSD to obey my wife. We've trained him in basic obedience (no, heel, sit, down, stay, come). My dog ignores my wife's commands when he becomes even slightly excited because he wants to play or he sees a strange person or another dog.

He obeys me on the first command as long as I use a deep, stern voice. I've found that he is much slower to obey if I don't.

My dog often gets bored and uses a very high pitched bark to get us to play with him. With my wife, he will escalate to the point where he runs in, nips at her pants or shirt, and then runs away to get her to chase him. My wife has corrected him as you describe for over a month, but he still doesn't seem to take her seriously. I think he sees her as more of a playmate than a master.

He will also completely ignore my wife if he sees a strange person or a dog. He will bark at strangers and will run to play with other dogs. We usually play and exercise with him about 30 to 60 minutes a day. My wife uses the sternest voice she can muscle when he ignores her but it doesn't work.