You can teach a horse to do anything with any cue you want by being 100% consistent. My stallion has been shown in reining and does every maneuver on a loose rein and no mouth contact.
By sitting deep in my saddle and pushing my legs forward, he will slide without saying 'Whoa!" When he is stopped, he will back 10 feet or 50 feet (picking his feet up and not dragging them) just by me putting my feet forward. No voice command, no lifted hand, no leg pressure.
He will spin when I take an inside leg off of him and "cluck".
You can end up with whatever aid you want in this way. I call it 'trading aids'. You start out with whatever aids you normally use to teach the maneuver you are training the horse to do. Then, you gradually use less of the perceptible ordinary aids and keep using more of the aid you want to transfer the 'cue' over to.
Like a sliding stop -- you start out doing whatever it takes to teach a sliding stop. You will be using reins, voice, seat and legs. The better the horse gets at stopping, the less rein pressure you use. Gradually you get to the point that you need no rein aid, little or no voice and shifting weight in the saddle and pushing both feet forward and the horse will stop as hard as he will with any other aids applied.
You always keep your other aids close and where you can correct the horse if he does not perform the maneuver at top form. But, the most important thing to remember is that you have to sit there and be 100% consistent from day 1. When a rider's hands and legs are all over the place, they will never have a 'finely tuned' horse that listens to the invisible aids of an expert rider.