First off, he's only 5 and should not be giving you attitude or allowed to talk back. You can remain calm but do insist on respect and manners or he'll do this with everyone and I doubt you'd like him to act like this to a teacher or a police officer some day. Remember, you are his parent, not his best friend. You have to do what's best for him even when he doesn't like it because you want to raise a polite, respectful law abiding citizen some day. It starts at home. Give him time outs when he acts out and have him apologize for his actions. It will take time and patience but it does work. Best wishes.
Is this the first time he has had to get up and go to school? Is it a kindergarten or a preschool. do his teachers report any of the same behavior?
I know that children have a hard time being rushed around in the mornings so how about you set the clock and give him longer time to get ready.,let him do it in his own time ..Is he copying anyone when he puts a voice on and copies you, very often children learn from others in their family ,has he an older brother, they like to copy siblings .Have you also thought that if you focused on his positive side it may be a good thing, praise him when you see him doing something right .Good Luck