This Rottweiler, "Sinbad", belonged to my best friend.  He was recently put to sleep after several lengthy health complications.  He was a sweet, gentle, SMART family dog ... great with her kids.  She often called him her "first born".  He was one of the smartest, most well behaved dogs I have ever met and I swear he understood English better than most people.  He'd cock his head when you would talk to him and you would see the intelligence in his eyes.  He was slavishly devoted to his "girlfriends" (my two greyhounds) and we got together for walks often.  My friend was devastated when she had to have him put to sleep.