Didn't you ask Finn?
Is there doggie sign language for the hard of canine hearing?
He has the basics. Raised index finger means sit. Pointing downward means lay down. Outstretched hand palm up means "paw". Hand held above head followed by a downward point means recall.
He obviously has to be looking at me for these to work. We haven't got as far as signing, "Why is this crossing called '5/13 Taunton', Finn?"