@madie4589 I have just read your post about the neighbor's and their Shepherd. If I were you-the best bet is to put up a high non see through fence. I have had German Shepherds, and hearing about the owners of this one-sounds like the kind that wind up in court because their dog,"who doesn't bite" had seriously hurt someone's dog, or child. My shepherds were worked with a lot,but they were protective,and most are just naturally that way-more so than doberman's and many other larger breeds. I, personally would NOT try to introduce Frank and that dog. I truly believe one day that dog will get over the fence,and hurt Frank. You can tell by the type of barking and body language, if it is barking because things are new, or barking/dangerous. It just sounds like the neighbors are just the type that shouldn't have that kind of dog.
Don't get me wrong, I love GS's but they have been the most "serious" dogs I have ever had. Be careful.