Yesterday, Laddie's only training was a short T-drill session in our side yard, using a target lining pole, verbal "sit" cues, and silent casts to white 2" bumpers not visible till the dog was close.
During the first few retrieves, Laddie showed no inclination to vocalize, so for last few, I introduced a verbal "over" cue to accompany the casts. My intent in the future is to rely primarily on silent casts, but have the verbal available if difficult factors such as a headwind or high cover suggest that more emphasis is needed. Today's work to us one more step toward rebuilding Laddie's handling skills without vocalization.
By the way, I don't know whether I've mentioned before that all of our devocalization work this last week has been done with white 2" bumpers, which I call puppy bumpers. These are the bumpers I use when just playing fetch with Laddie, and I think they may have a somewhat more lighthearted association than the full-sized 3" bumpers we normally use for training.