The saddest thing about one of my old dogs going deaf was that she stopped doing this characteristic playful “bark.” It wasn’t really a bark, more of a cute little howl that came out sounding like, “Roooooo.” I used to “talk” with her by making that sound and she’d “roo” back at me. But when she lost her sense of hearing, she couldn’t respond to my “roo” anymore and stopped making the sound entirely. :(