There is a section on my website (you guys know I don't sell nuffin) under "Question Corner" called "The Voice" -- it's some silly exercises very similar to what the breeder is talking about.
It's hard for we humans to really understand how the sound of our voices can wind a dog up. Either inadvertently we can make things worse, OR we can ignore a perfect opportunity to use our voice as a 'reward'. What she's telling you do to is good stuff.
True story -- Billy is very food-motivated BUT even more, he is attention-motivated. Not just petting and loving BUT "star of the show" kind of thing. When we adopted him he had many many training issues - he'd been abused (which didn't show up til after the adoption) and obedience class was VERY difficult. He was so terrified of going into a 'down' he would literally stand and shake until his teeth rattled.
He also had a terrifed/fear aggression because he'd been abused by some little about-age-7 blonde girls.
By the time he decided being with us was the greatest thing since kibble, he also had worked himself into a fair-sized dose of separation anxiety -- and trying to train him to do a "sit/stay" while I walked 20 feet away from him with my back TO him and then for him to not break that stay til I called him? Wow .... talk about a challenge.
I discovered quite by accident (because it's a "me thing" to talk with my hands) that I could walk away from him with my back to him, but could reassure him by gesturing a 'stay' behind my back. "ok .. she hasn't forgotten me".
But then the big huge payoff -- When I'd get to that 20 foot mark, and turn - I would give him this big "I'm bored ... I think I'll stand here for a while and YOU need to stay there too because I haven't called you ..... YET!!!" look.
I could stand there, rub my toe in the dirt, look at the sky ... fool around and his expectation would build like a rocket about to blast off. FINALLY I would put a HUGE grin on my face, throw my arms out and scream "COME TO ****MOMMMYYYYYYYYYY***" and he would bolt to me like he was taking off for Jupiter.
It was hysterical. Every week those in our class used to just go into hysterics waiting for Billy to 'wait' for me (while their dogs may or may not break a sit and might wander over to see another dog instead of 'comng' straight to them).
But he was doing it FOR THE APPLAUSE. He *KNEW* this was a big huge Billy-sized opportunity to have the world look at him and go "AWWWWW he's SO cute!!"
My point is this -- get to know *this* dog. Know what truly, deep down, trips this dog's trigger ... what motivates THIS dog, what distracts ... what focuses them. And USE it.
You may find that your *voice* ... with this dog ... is key. Your dog will learn that 'Ohhhh boy ... Mom's SERRY-US' tone and will just plain not punch your buttons.
But then -- it will bite you because you can't over-use a thing that 'works' or they'l .... *sigh* ignore it!!
and btw -- the thing we finally foudn that was the key to a down stay? While we were here at home, no pressure, no 'training mode'-- just sitting around chilling -- when I would see him lie down of his own accord I would say TO DAVID "Wow ... Billy is doing such a GOOD 'lay down'!! That is a great 'lay down' isn't it David?"
"yeah, boy that is a GREAT lay down!"
He came to re-associate the words with no pain, no stress, just "hmm, I'm not doing nuffing but laying here -- THAT is all they want?"
Gradually after seeing him "lay down" and commenting to each other -- we began to address him directly "GOOD lay down Billy! good job!" And then call him from that position to us to "lay down" with a reward. It took almost 2 months to extinguish the fear and retrain ...
But that's why stuff like clicker training can work -- isolating a behavior so they know THIS ... this exact second ... is what you want.
But it's all under communication. Sorry this was long -- and your dog hasn't been abused, but challenging training IS ... a challenge!