I train my cat and while I can't always understand her I think one of the most impressive features of the human mind is to be able to have such great understanding of others. We have theory of mind, joint attention, triadic awareness, and much more. My cat can understand me a bit but it's definitely asymmetric.
It's definitely not easy to understand other animals. As Wittgenstein suggests, their minds are alien to us. But we seem to be able to adapt. I'm much better at understanding my cat than my girlfriend (all the local street cats love me, and I teach many of them tricks) but I'm also nothing compared to experts I've seen.
Honestly, I think everyone studying AI could benefit by spending some more time studying animal cognition. While not like computer minds these are testable "alien minds" and can help us better understand the general nature of intelligence