They identified nouns and adjectives in prairie dog communication, that also seems to vary with regional dialects. I'll try to remember to dig up a source when I'm not out and about later.

Edit: here's a not fully scientific link, but has names and links for people who want to go deeper in the science while being a decent lay person's overview.

Yes, the blog name isn't very scientific looking (I have not read anything else on it). https://thehumanevolutionblog.com/2015/08/18/a-career-studying-the-sophisticated-vocabulary-of-prairie-dogs/

And here's a peer reviewed study: https://www.sciencedirect.com/science/article/abs/pii/S0003347205801174