Even though dogs don’t speak our language, most dog owners will agree that it's easy to communicate with them. They can learn to interpret our instructions based on cues that we give them, but they are also capable of conveying messages themselves. Aside from barking, dogs can convey a lot about how they are feeling through their body language. A wagging tail can mean they are happy, but in combination with different postures, it can mean something else entirely.
For Jayden the dog, hearing his name from a family member is enough to get him excited. However, when he starts to wag his tail, poor Rosie is caught completely off guard by what Jayden does next.