Just wondering but I've a couple of Western neighbours who can't speak Thai very well but when they're out with their dogs I hear them speaking Thai to the mutt!
"ma nee", "reo na" etc. Maybe they're insane or trying to show off?
I have 5 dogs, and although I speak Thai, would never dream of speaking Thai to any of them. Actually I don't talk to them in English very often either, apart from my long time 10 year companion, Whisky, a golden retriever, that is more intelligent than most locals.