One of the main sources of misunderstanding between our dog and cat is competition for territory. This will most often occur if we have failed to properly set up their environment as I recommend above. Also, a feline can be very difficult to live with, especially if he is the first one in the household. They can develop a sense of belonging. Thus, his attachment to us will make him very guarded with regards to his environment. He can even be violent towards our new friend.
However, our dog will often opt for a more serene posture accompanied by calming signals. Even if our dog was there first, he will do everything to lighten the mood.
However, the difference in language will cause a second possibility of misunderstanding. Indeed, the communication signals between our cats and our dogs are totally opposite. They don't speak the same expression at all, creating a major obstacle in their relationship. For example, the dog wags his tail when he confirms his joy and his desire to play. For the cat, it means annoyance or even a warning. Our pets will have the additional challenge of learning a new language.