After rescuing a few dozen dogs, I have learned how to talk dog.
It is an easy language to understand because dogs are commutative.
All you have to do is to observe and listen. They understand when you
are sad, happy, or silly. And they certainly know when you are planning
on going out and leaving them alone.
Packing your suitcase for a trip is a sure trigger.
You can hear them say, "Don't you realize that you
will be leaving me behind?
Why can't I come with you?"