I think it goes far beyond just our behavior with dogs. They can sense how we "feel" about them, despite how we "act", and they respond accordingly.

We recently added 2 baby toy poodles, (sisters) to our family, with the intention that one of the girls would be my daughter's, (who's 14), and the other as mine.
All went well for the first couple weeks. Nilla, (my dot's pup), was responding well to her until dot began to lag on her attending to her. Naturally, I became the initial caretaker of both.
Since, Nilla's attention diverted over toward me as her "mommy", instead of my dot, as Nilla didn't sense the love from my daughter as she received from me.

My daughter began to mention how Nilla doesn't "love" her. I told my daughter, that telling her pup hello when she felt like, then shoving her aside the rest of the time it isn't enough to form a bond. That bonding means....accepting responsibility of the pup...the good and bad.
Also, any animal will not respond favorably to a fearful situation, (with yelling as one of them). To form a bond with an animal, you must FIRST gain their trust..and that wont happen when they sense fear.

If you really want to form a lasting bond with your dogs, then you have to first understand that you receive what you invest.
"Acting" like you want their companionship isn't enough. They know better. You have to "want" their companionship. In order to obtain their companionship, you have to earn their trust.
Your grandmother "baby talks" them because it's how she "feels" about them. To her, they are her loved ones.
I do the very same thing with my pups...to me they ARE my babies. Naturally, I attend to them exactly as such no matter the situation. I'm constantly talking "lovies" to them, (my hub and dot think I'm odd for that, but it's how I "feel" about them). And they respond by following me everywhere, under my feet constantly...etc.

A great way to begin a bond is by being the one who feeds the dogs. Perhaps, you can be the ONLY one who feeds them...and when you do, talk to your dogs..(lol...I know that sounds odd, but...they DO know the difference).

Hope that helps some....
Shangrala