Kennel cough commonly sounds like a relentless dry hack usually ended with a wet vomit sound.
Videos of Kennel Cough
Chihuahua with kennel cough video
This video is a fantastic mix of the different ways that kennel cough can sound. Please remember that kennel cough commonly masks other more serious diseases and it is important to get your dog checked out right away by an animal professional.
Small dog with kennel cough video
As you can see in this video, kennel cough can often sound like a loud honking noise.