Always use the same language structure. Always react the same way. Always show love. It doesn't take long for a dog to recognize words and tones of voice. It took some training of myself to get to the point when I would look her in the eye and speak to her firmly, but not loudly or angrily.
Negative emotion appears as attention and reinforces bad behavior.
Using the same tone of voice and the same words for a command made Amie pay attention to what was being communicated to her, rather than being diverted by the affect in the voice or being confused by the words. Getting the tone right and being consistent was a break-through in training Amie. My sister adopted a dog that had been trained as a work dog. The manual empowered me to not be afraid of Amie but to recognize her native intelligence. The manual said that when you crouch or squat and speak to the dog, the dog sees this as a submissive position.