The dog bounds into the house. If he were human, he’d be saying, “Mom! Mom! Guess what? We saw this squirrel? It walked right onto the sidewalk and then ran away! You should have seen it!”
I don’t believe that he has this thought or that his objective is to transfer information about the squirrel to a human. But his behavior–other than the words–is exactly like that of a 7-year-old who just had an exciting experience outside.
It makes me think that the behavior is generic: both species like to communicate excitement when seeing a loved one. You can imagine that this desire is adaptive for social animals. Humans just happen to use words for the purpose.
A bunch of geese gather in a rough circle. One is backed up and hissing. Most of them are honking and splashing their wings aggressively, perhaps forming two opposing groups. If they were humans, they would be deeply invested in the precise content of their words. “You always say …” “Yeah, well, you promised …” “I know what you’ve been saying behind my back …”
Again, the behavior is exactly the same as ours, but we care about the propositional content of our words, and the geese don’t need that to establish boundaries.
These are just some untutored speculations at the border of ethology and linguistics–which is, of course, a topic for real science. For me, the takeaway is existential. Let’s recognize that all the detailed things we think and say are not all that important; we’re just exhibiting behaviors.