It's interesting how she matches the pitch of her voice. Obviously hearing words in the response is meaningless to the dog, but the dog's deliberate effort to match the sounds created by others in the pack is actually kind of interesting.
As a matter of fact, that's the normal "pitch" of Husky dogs. They are physically unable to bark, so they howl something closer to wolves, exactly like what we have heard here.
There's nothing out of the ordinary here. This dog has not been trained.
"A man who only drinks water has a secret to hide from his fellow-men" -Baudelaire