When it comes to dog training, you all know I'm about as positive as they come. My methods are science-based and I don't use aversion. I have even done my best to move away from verbal corrections like "ah-ah!". Before I lose you, let me explain a little further.
Our dogs don't speak English and they never will. Essentially we are pairing sounds with actions when teaching our dogs verbal cues. It's always recommended to teach a behavior with a hand or body cue first and then pair a word to that action once it's solid. Our dogs are watching us more than they are listening to us. That means we need to be really careful with how we compose ourselves and the movements we make when teaching our dogs.
I have never used the word "no" in my training. The reason being that there is "no" and "know" in the English language. This matters because if you begin to teach your dog that "no" means to stop their current behavior (e.g. your dog jumps on you and you say "no") then this can easily back fire on you when you're no longer talking to your dog.
For example:
You ask your spouse, "did you know we had a birthday party this weekend?"
Your spouse replies, "No, I didn't know that."
The sound no/know was just said three times in that two sentence conversation. During this conversation your dog was laying down by your feet being calm and polite. However she was just verbally corrected three times (which to her means, don't be calm) and now decides to get up and go chew on a shoe or chase your child.
This is the problem with using "no" as a correction word. Can it work, sure. Can it also be confusing from day to day, of course. Are there better options, yes.
I used to teach my students to say "ah-ah" instead of "no". That way, you wouldn't have to worry about accidentally saying your correction word in conversation. For example, if the dog jumps for the treat as you ask for a sit with your hand cue, a quick "ah-ah" was a way of letting them know that they did something wrong. However, you also need to take the treat away for the dog to understand that "ah-ah" is a correction, and good things go away when you say it. Did this work, yes it did most of the time. Was it also annoying saying "ah-ah" many times while teaching my classes and with my own dog at home, definitely! So I tried something else.
In the same scenario above, I decided to take away the treat more obviously and not say anything this time. So instead of pulling the treat away slightly when the dog jumped, I did a quick snap of my elbow to do a sort of 'out of sight, out of mind' and hid the treat in my hand. Timing is important here (as it always is in dog training), the moment the dog jumps, the treat goes away. The moment the dog goes back down to all four feet on the floor (four on the floor) the treat comes back and you show the hand cue again. Once the butt hits the floor and no jumping occurs, I mark and treat. Marking is another topic for another day. What I'm getting at here is that instead of constantly saying "ah-ah", all I had to do was pull the treat away. That's a pretty big punishment for a dog that really wants that piece of food. Did this work, yes. Was it more efficient than saying "ah-ah", also yes! As a trainer, it's important to me that I continue to develop my skills, and evolve from the information I get. That's not only going to make me better at what I do, but also make it easier for my students and their dogs.
I haven't taught a class with "ah-ah" in over a year. I also have noticed better results in all aspects of training. The dogs are bonded more with their parents because they aren't constantly saying negative words, the parents aren't feeling like they have to continually correct the dog with their voice, and the dog learns the cue faster because we removed having to use your voice which helps the parent focus on the task at hand. There are still some occasions where I feel "ah-ah" is necessary, but it's few and far between.
Now let me get to the ways in which "no" can be useful in dog training. HINT: it's actually more people training than dog training.
As already mentioned, you don't really want to or even need to say "no" to your dog. However you are going to have to say it to other people, a lot. When I teach my classes and do my in home sessions, I generally like to teach people the etiquette of proper people+dog greetings and dog+dog greetings. This way, when the opportunity arises, and it will often, you have a successful training moment versus having your dog learn they can do whatever they want and still be rewarded.
There is a lot to proper greetings, especially when it comes to dog+dog greetings. If you or your dog struggle with this I highly encourage you to hire a positive, science-based trainer to help you learn how to do it appropriately. The main concept though is basically, you want your dog to receive pets or attention from a dog or person and not have them overreact by jumping, scratching, biting, etc. If you feel like your dog is going to jump on the person approaching you then don't be afraid to let that person know that now is not a good time to pet your dog. Always make sure people ask before petting your dog too. I have had to teach countless adults and children this seemingly obvious rule. If they don't ask, stop them and instruct them that they should.
In training, you always want to set your dog up for success. If you go too fast and push your dog too hard you'll end up setting them back and the training takes longer. When I'm working with a dog that is overly excited for people and/or dogs, I always tell the parent that they shouldn't be afraid to tell people "no" when they ask to pet their dog. If the parent feels their dog is not going to be able to calmly receive petting, but they allow the people to approach and greet the dog anyways, then they just set their dog up for failure. DO NOT DO THIS! I understand it can be hard to be so assertive with strangers and the fear of coming off as rude is real. However, you will probably never see those people again, but you have to live with your dog. Don't let that fear stop you from keeping your training in the successful zone. I have worked with dogs that were so stimulated by people and/or dogs that we had to do many weeks of desensitization work before the dog could even be expected to handle having a stranger hold out their hand. It takes work and patience but this will keep you, your dog, and others safe. You don't want your dog jumping on someone and knocking them over, or scratching/biting them. This makes your dog a liability and a training protocol should definitely be put in place.
The same goes for dog+dog greetings. So many more factors play into proper dog+dog greetings such as body language (e.g. just because the tail is wagging doesn't mean they want to greet), pet history, equipment being used, etc. As stated before, if you feel your dog needs help with this please seek out a positive, science-based trainer to help you achieve success. If you have a dog that gets overly excited/timid/anxious for other dogs, you should once again not be afraid to say "no" to the approaching person and their dog. All too often, people assume that because their dog is friendly, all other dogs will be friendly. This is clearly not the case and many fights happen between dogs because of this. If a person approaches you with their dog and says something like "do you mind if they say hi?", you should definitely say "no" if you feel like your dog won't be able to handle it. I have worked with dogs on both ends of the spectrum some very happily wanting to say hi, some very upset at the presence of another dog; and in both cases saying "no" is the smartest thing to do. A dog fight is incredibly dangerous for a dog both physically and mentally. Please be cautious and courteous to other dogs and their owners.
I also want to make sure you all understand that you're going to have to say "no" to your family and friends, and even spouses and children and that is okay. Family and friends loves to interact with the new puppy, or the newly rescued dog. They also love to do inappropriate things with them such as feed them table scraps, let them jump all over them, and yell words and corrections at your dog without even asking you if it's okay. This is something that, as a trainer, drives me crazy! I cannot stand it when family or friends decide to ignore anything you've instructed them to do and go about doing their own thing with your dog. I have had to get serious with my own family a few times. Such as saying, "stop repeating that word, you're confusing him." or "Don't feed him those table scraps, you're cleaning up the diarrhea if he has it." My family tends to listen to me quickly probably because I'm a trainer. However, I want your family to listen to you too. If "no" doesn't work for them, I recommend putting the leash on your dog, even in the home, and keeping them next to you. This way, you can observe and teach others how to interact with your dog the right way. Put it this way, if you hired a babysitter for your children and told them "no sugar after 6p." and then come to find out the babysitter did give them sugary foods after 6p, you would never hire that babysitter again. The same should be expected for your dog. Your dog is your four legged child with sharp teeth and nails, and they can be strong too. We want to make sure they are learning things the right way. I expect people to follow the rules I give them for interacting with my dog. If they decide to ignore my rules, then I kindly (sometimes not so kindly) let them know that until they can follow my rules, they can't interact with my dog.
Finally, you should also learn to be okay with saying "no" to popular dog socializing areas such as day cares and dog parks. These places can be overwhelming to many dogs, and not actually fun for them like you might think. Many people find out the hard way that their dog doesn't enjoy these areas after the dog gets into a dog fight or is so scared they won't even go in. Don't subject your dog to an environment they don't like just because you think it is good for them. Learn to read your dog's body language so you can better understand whether they truly enjoy the environment or not. If your dog is pulling you into the door of the day care center, you are probably okay to leave them there, however if they don't really seem all that excited maybe it's best to research another route to get them the proper socialization they need.
As I said in the beginning, this is all about people training. You have to teach yourself that it's okay to tell people what to do with your dog, and that saying "no" to them isn't a bad thing. Ultimately, you want your dog to learn and have fun and be successful in life. Make sure you are setting them up for such moments by being the amazing dog parent you know you can be.
Happy training!