https://drsophiayin.com/wp-content/uploads/2015/04/Yin2004Ba...
Some less-dense coverage:
https://www.star2.com/living/2018/02/27/ev-when-your-dog-bar...
"All the people were pretty good at figuring out what was going on. There were no significant differences between dog owners and non-dog owners. They were particularly good at identifying dog emotion in Stranger Danger, Guard Dog, Alone, and Play."
These are interesting studies, but many nevertheless wonder why scientists bother. Most of us understand a common language for terrestrial animals. Lower-pitched sounds come from bigger animals with bigger throats. I've never been growled at by a lion, but I would understand that a deep low growl means it is trying to scare me with its size. This holds true for bears, dogs, cats, deer, even humans. Conversely, high-pitched screams are generally calls for help, mimicking the pitch of the young. Showing your teeth is a near-universal sign of aggression. Put this all together and it is enough to satisfy most definitions of language.
