Your tone of voice matters when communicating to your dog.
There are three main voice tones that we can use to clearly communicate what we want from our dogs. If we want the dog to calm down, we should use low, long and slow tones, such as, “Gooood doooog,” spoken in a low, calm and steady voice. This has been shown to help pacify a dog.
The opposite of that are higher pitched, short words that can be used to generate excitement in our dogs. If we want to help motivate our dogs, get them moving or engage them in play, we could excitedly shout about, “Puppy! Puppy!” in high pitched voices to get the dogs interested and excited. 
The third tone is one we give off when we are frustrated or angry at our dogs, and our dogs know it. Dogs are sensitive to our emotional state and the moment our frustrations leech into our voices and our body language, dogs will start to response less to us and hesitate more. If you are trying to effectively communicate with your dog, frustration is a sure way to halt all effective communication between you.
If we want to communicate better with our dogs, we need to ensure that we are using the right tone of voice, one that fosters listening and not avoidance.