Dogs definitely know about the concept of "danger". Roaring fire, a raised stick, or loud noises. These are all things which doesn't cause immediate pain but they react to avoid them. It seems from the story Lenny includes in the things he want to avoid the ocean while Arthur doesn't. That sounds more like an individual difference than a genetic predisposition.
You don't need to speak a foreign language to have this concept.
I don't know what is your definition of "persuasion". If it involves the behaviour of standing in someone's way and bothering them until they turn back then we can agree that Lenny seems to have the concept despite not having a language.
We had an Old English Sheepdog called Bob who let kids climb trees but only up to a certain height. If you went higher Bob grabbed your ankle and gently pulled you back to the height he previously "let you". Otherwise you could do whatever you wanted to do on the tree and he didn't care. Otherwise never herded anyone ever.
My point is not the language. More that if a chinese coast guard would drag you out of the sea you wouldn't be saying "yeah the chinese have a strong herding reflex". You would say "this person doesn't want me to swim", or "this person thinks I'm in danger and I can't communicate that I'm not".