Common sense about horse communication (Relaxed and Forward). "Be curious in silence."
Tania Kindersley, in The Happy Horse, shares a similar sentiment: "...the really great horsemen and women have the gift of stillness. One of the greatest presents you can give to your house is to leave it in peace..."
Beyond communicating, I believe there's even more going on here. John O'Donohue, as quoted in Terri Windling's blog post, The philosophy of compassion (Myth & Moor): "Because the animals live essentially what I call the contemplative life, maybe the most sacred prayer of the world actually happens within animal consciousness."
I might have more to say on this topic but I think I'll just shut up and practice.