So it should have been no surprise to me that when re-reading parts of James Lamb Free's Training Your Retreiver the other night I saw that he had come to the same conclusion 60 years ago. (So much for my reading comprehension.) At any rate, Free makes some excellent points about sounding like a dog trainer.
"Nearly all beginning trainers just sound too damn wishy-washy when they give a command. I don't mean you should yell every time you speak to a dog. Certainly not. But you should always speak with plenty of firmness in your voice, and when necessary, even sternness. You should sound as though you mean it, and as though you expect instant obedience, as a matter of course. You'll get it, if you can put this over in your tone."_