I have truly never met a rider who doesn't use verbal cues ever. I know lots of riders in many disciplines (but not dressage admittedly--but OP isn't a dressage rider anyway). I use verbals as reinforcement. If my horse isn't moving off my legs in a timely manner I'll click to him. I also like my horses to stop with just a "whoa" and a deep sit. As to the subject.... I suck at extended trot also so I'm here to learn. Prime reason I don't do HUS, ha!