Steps and a cough

 It seems things are picking up. Today, I was again at the computer in the library, my dog stretched out comfortably on the rug between the library and diningroom doorway. The distinct sound of approaching footsteps came from the vicinity of the kitchen and into the diningroom, then a cough was heard; kinda like someone clearing their throat. As my wife worked today (even though it is newyears day) the steps didn't surprise me because the time for my wifes arrival was about right. The dog looked up and toward the dining room but made no move to welcome my wife home. Just about that time my telephone alert sounded on my computer saying I had an incoming call. I took the call; it was my wife calling to say she would be late as the store was still full of customers. So ,once again, the steps and cough could not be attributed to her and theres no one else in the house. My dog must be getting use to these steps , they use to really bug him either sending him looking for the intruder, or into barking or growling fits. Lately he simply looks up and goes back to sleep or whatever he does when zonking out on a rug. This whole phenonema is quite strange and I'm sure the real answer to it would be most interesting.