The head tilt of a dog is an adorable feature we humans seem to melt with. In the case of a puppy, it doesn’t matter what kind of trouble he got himself into, one tilt of the head and a smile is brought to our face and all is forgiven.
Some speculation includes:
Tilting their heads can make a dog either see or hear better:
There is some thought that although dogs have a keen sense of hearing, they are tilting their heads to hear certain sounds or phrases better. Psychologist Stanley Coren theorizes that dogs with longer muzzles tilt their heads more often and it is most likely in order to see the person better. When you think about it, it would be hard to see a person’s whole face if you have a big muzzle. Tilting their head can aid the dog in seeing the person’s whole face.

In expectation of something:
Tilting the head may be used when a dog is ready for an action to be made by thee human (Like giving a treat, or throwing a ball)
Lizzy in anticipation
Trying to understand something:
Dogs may tilt their head if they are unsure what you are trying to tell them and they are trying to figure it out.
