It depends on what I say or convey in my voice........
Yes, my dog understands these commands:
lay down , now
stay by me
you are on duty
want a treat?
He does not understand:
When is double coupon day at the grocery store
Would I get better fuel mileage by a smaller bore stroke
Should I add a hint of nutmeg to this pudding
While my dog is well behaved, and responsive, most of it reflects the intellegience that it takes to be obedient and protective, not an understanding of complex human communication.