Here's some advice on how to effectively communicate with your four-legged friend.
Like most people, I talk to my dogs (and my cats). I tell them when I'm leaving, how long I'll be gone, when dad will be home...pretty much everything you would tell a human child. I know they don't understand me, but it just makes ME feel better if I act like they do.
What most people don't take into consideration when talking to their dog is that dogs don't ACTUALLY understand english. They understand "sit", "down", and "stay" because we have helped them learn that when we say a certain word, they should act a certain way or perform a certain behavior. You could literally use the word "potato" instead of "sit", and as long as the dog makes the association, he will sit whenever you say "potato".
On a side note, I saw a very cool video of a dog who's commands were all spells from Harry Potter, perfect example of the above paragraph.
Back to the point...dogs do not understand English (or any other language besides dog), or punishment, like we do. If you tell your dog "NO!", sure they might stop what they are doing, probably because they've learned that after you say "no," something bad will happen if they don't stop. So they stop to avoid whatever negative consequence usually follows. This is a form of what I like to call management. You are essentially preventing your dog from doing something he's not supposed to do, but your not telling him what he should be doing. For example, if you catch your puppy (or adult dog, I don't judge!) peeing in the house and you immediately yell "No!", he might stop, but you aren't telling him where he should be peeing instead. Simply yelling "No" will just teach him not to do it in front of you. Instead of yelling at him, say "outside, outside, outside!" and quickly, but gently take him to the place where he should be peeing. Not only are you no longer yelling, but you are telling the dog what you want him to do.
Lesson of the Day: Don't yell at your dog. He doesn't understand you. Instead of yelling at your dog when he behaves inappropriately, redirect him and tell him what he should be doing!
***Note that if you are redirecting your dog, only say the command once. If you say it over and over, you run the risk of desensitizing him to the word. For example, your dog jumps on people to greet them. If you tell him "Sit, sit, sit....Fido sit" all in the span of 5 seconds and he doesn't do it or doesn't do it until the 15th time you say it, you are teaching him that he can ignore you and sit whenever he decides its time to sit or not sit at all and still get away with it AND get all the attention he wants.